Qualcomm
200+ Interview Questions and Answers
Q1. Bridge and torch problem : Four people come to a river in the night. There is a narrow bridge, but it can only hold two people at a time. They have one torch and, because it's night, the torch has to be used wh...
read moreFour people with different crossing times need to cross a bridge with a torch. Only two can cross at a time. What is the least time taken?
Person A and B cross first, taking 2 minutes
A goes back with the torch, taking 1 minute
C and D cross together, taking 10 minutes
B goes back with the torch, taking 2 minutes
A and B cross together, taking 2 minutes
Total time taken is 17 minutes
Q2. Given an array A[n], write a C program to find P and Q (P>Q) such that A[P] - A[Q] is maximum
C program to find P and Q (P>Q) such that A[P] - A[Q] is maximum
Iterate through array and keep track of maximum difference and corresponding indices
Initialize P and Q to first two elements and update as necessary
Time complexity: O(n)
Q3. What is a deadlock? How to know if a deadlock is present?
A deadlock is a situation where two or more processes are unable to proceed because they are waiting for each other to release resources.
Deadlocks occur when two or more processes are blocked and unable to continue executing.
To detect a deadlock, look for circular wait, hold and wait, no preemption, and mutual exclusion.
Examples of deadlocks include a printer that is waiting for a user to replace the paper tray, or two trains that are stuck on the same track waiting for each ...read more
Q4. What are the basic functions of OS?
OS functions include managing hardware resources, providing user interface, and running applications.
Managing hardware resources such as CPU, memory, and storage
Providing user interface for interaction with the computer
Running applications and managing processes
Managing file systems and data storage
Providing security and access control
Managing network connections and communication
Performing system updates and maintenance
Handling errors and system crashes
Virtualization and con...read more
Q5. A pyramid is given many blank spaces. Condition is that number in a cell equals sum of numbers in bottom two cells. Fill the blanks
The question asks to fill the blanks in a pyramid where each number is the sum of the numbers in the bottom two cells.
Start from the bottom row and work your way up, calculating the sum of the numbers in the bottom two cells for each blank space.
Use a loop to iterate through each row and column of the pyramid.
Store the calculated sum in the corresponding blank space.
Repeat the process until all the blanks are filled.
Q6. What is scheduling? List different types of scheduling
Scheduling is the process of allocating resources to tasks based on priority and availability.
Different types of scheduling include: preemptive and non-preemptive scheduling, round-robin scheduling, priority scheduling, and deadline scheduling.
Preemptive scheduling allows higher priority tasks to interrupt lower priority tasks, while non-preemptive scheduling does not.
Round-robin scheduling allocates a fixed time slice to each task in a cyclic manner.
Priority scheduling assig...read more
There is a one-dimensional garden of length 'N'. On each of the positions from 0 to 'N', there is a fountain, and this fountain’s water can reach up to a certain range as explained further. In ...read more
You have been given a sorted array/list ARR consisting of ‘N’ elements. You are also given an integer ‘K’.
Now the array is rotated at some pivot point unknown to you. For example,...read more
You are given an arbitrary linked list consisting of 'N' nodes having integer values. You need to perform insertion sort on the linked list and print the final list in sorted order....read more
You need to implement the Stack data structure using a Singly Linked List.
Create a class named 'Stack' which supports the following operations(all in O(1) time):
getSize: Retur...read more
Ninja has a number ‘N’. He wants to print the pattern in such a way that the outer rectangle is of the number ‘N’ and the number goes on decreasing as we move inside the rectangles.
For exam...read more
Given 'N' number of intervals, where each interval contains two integers denoting the boundaries of the interval. The task is to merge all the overlapping intervals and return the lis...read more
Q13. How many ways would one arrange sets of coloured balls, the first set all red, the next all blue, and the last all green, and all balls in a set are identical, in a line?
The number of ways to arrange sets of coloured balls in a line.
The number of ways to arrange the red balls is the factorial of the number of red balls.
The number of ways to arrange the blue balls is the factorial of the number of blue balls.
The number of ways to arrange the green balls is the factorial of the number of green balls.
To find the total number of arrangements, multiply the number of arrangements for each set.
Given an integer N, print all the prime numbers that lie in the range 2 to N (both inclusive).
Print the prime numbers in different lines.
Input Format :
Integer N
Output Format :
Prime number...read more
Q15. What is Min-Cut placement algorithm? Given some block sizes, use the algorithm to place them on a given chip area
Min-Cut placement algorithm is used to place blocks on a given chip area.
Min-Cut algorithm partitions the chip into two parts and minimizes the cut between them
It is a graph-based algorithm that uses a flow network to represent the chip and its blocks
The algorithm iteratively partitions the network until all blocks are placed
Example: Placing logic gates on a microprocessor chip
Q16. How do you implement the overlap-add method of convolution?
Overlap-add method of convolution is implemented by dividing the input signal into overlapping segments and convolving each segment with a filter.
Divide the input signal into overlapping segments
Apply the filter to each segment
Add the convolved segments together to get the output signal
The length of each segment should be greater than or equal to the length of the filter
The overlap between adjacent segments should be greater than or equal to the length of the filter minus one
Q17. What are the advantages of having multi-core processor?
Multi-core processors provide faster and more efficient computing.
Improved performance and speed
Ability to handle multiple tasks simultaneously
Reduced power consumption
Better multitasking capabilities
Enhanced user experience
Examples: Intel Core i7, AMD Ryzen 9
You have been given a directed weighted graph of ‘N’ vertices labeled from 1 to 'N' and ‘M’ edges. Each edge connecting two nodes 'u' and 'v' has a weight 'w' denoting the distance between them.
You...read more
Q19. Explain one CS topic(of your choice) in layman terms
Explain Big O notation
Big O notation is used to describe the time complexity of an algorithm
It helps us understand how the algorithm's performance changes with input size
O(1) means constant time, O(n) means linear time, O(n^2) means quadratic time
We want algorithms with lower Big O values for better performance
Given a singly linked list, you have to detect the loop and remove the loop from the linked list, if present. You have to make changes in the given linked list itself and return the update...read more
Q21. What is the difference between task, process and thread ?
Task is a unit of work, process is an instance of a program, and thread is a subset of a process.
Task is a single unit of work that needs to be completed.
Process is an instance of a program that is being executed.
Thread is a subset of a process that can run concurrently with other threads.
A process can have multiple threads, but a thread can only belong to one process.
Threads share the same memory space, while processes have their own memory space.
Threads are lightweight comp...read more
Q22. What is the difference between multi-threading, multi-processing and multi-tasking ?
Multi-threading, multi-processing and multi-tasking are different ways of achieving parallelism in computing.
Multi-threading is a technique of dividing a single process into multiple threads that can run concurrently.
Multi-processing is a technique of dividing a single process into multiple processes that can run concurrently.
Multi-tasking is a technique of running multiple processes or tasks concurrently on a single processor.
Multi-threading and multi-processing are used to ...read more
Q23. Delete a node from linked list when we are given a reference to the node. But the head pointer is not given.
To delete a node from a linked list when only given a reference to the node, we can copy the data of the next node to the given node and delete the next node.
Copy the data of the next node to the given node
Update the next pointer of the given node to skip the next node
Delete the next node
What is the output of following program?
# include
void func(int a){
a = 30;
}
int main(){
int b = 20;
func(b);
printf("%d", b);
return 0;
}
Option 1: 20Option 2: 30Option 3: compile error Opt...read more
Q25. What is parity and how is it used? Draw the circuit diagram for a parity checker
Parity is a method of error detection in digital communication. It involves adding an extra bit to a data stream to ensure even or odd number of 1s.
Parity is used to detect errors in data transmission.
It involves adding a parity bit to a data stream.
The parity bit is set to 1 or 0 depending on whether the number of 1s in the data stream is even or odd.
If an error occurs during transmission, the parity bit will be incorrect and the receiver can detect the error.
Parity can be u...read more
Q26. What are your location preferences?
I am open to relocation based on the job opportunity and growth prospects.
Open to relocation for the right opportunity
Willing to move for career growth
Flexible with location based on job requirements
Torch and Bridge
There are 4 persons (A, B, C and D) who want to cross a bridge in night. A takes 1 minute to cross the bridge. B takes 2 minutes to cross the bridge. C takes 5 minutes to cross the bridge....read more
You have been given an integer 'N'. Your task is to return true if it is a power of two. Otherwise, return false.
An integer 'N' is a power of two, if it can be expressed as 2 ^ 'K' where 'K' is an ...read more
Q29. Find the sum of two numbers without using any mathematical operarors.
Use bitwise operations to find the sum of two numbers without using mathematical operators.
Use bitwise XOR to find the sum of two numbers without carrying.
Use bitwise AND and left shift to find the carry.
Repeat the process until there is no carry left.
Q30. What is Moore's Law?
Moore's Law is the observation that the number of transistors in a dense integrated circuit doubles about every two years.
Named after Intel co-founder Gordon Moore
First stated in 1965
Has been a driving force behind technological advancements
Predicts exponential growth in computing power
Has been challenged in recent years due to physical limitations
Q31. Minimum no of steps needed to find the value of a nth order polynomial by making calls to a function that can compute the value of a 1st order polynomial( ax+b ). What is the answer if we can do parallel proces...
read moreThe minimum number of steps needed to find the value of an nth order polynomial is n+1.
To find the value of a 1st order polynomial, we need 2 steps (1 multiplication and 1 addition).
For an nth order polynomial, we need to compute n 1st order polynomials and perform n-1 additions.
Therefore, the minimum number of steps is n+1.
If parallel processing is allowed, we can compute the value of each 1st order polynomial simultaneously, reducing the time taken.
In this case, the number ...read more
Q32. What are static, volatile, const in C mean ?
Static, volatile, const are C keywords used to define properties of variables.
Static: used to define a variable that retains its value between function calls
Volatile: used to indicate that a variable's value may change unexpectedly, e.g. in an interrupt
Const: used to define a variable whose value cannot be changed once initialized
Q33. Differentiate between a process and a thread
A process is an instance of a program while a thread is a subset of a process.
A process has its own memory space while threads share memory space
Processes are heavyweight while threads are lightweight
Processes communicate through inter-process communication while threads communicate through shared memory
Examples of processes include web browsers, text editors, etc. while examples of threads include GUI updates, background tasks, etc.
Q34. Draw the state diagram and the clocked D-flipflop circuit for a 0110 sequence detector
State diagram and clocked D-flipflop circuit for a 0110 sequence detector.
The state diagram will have four states: S0, S1, S2, and S3.
The circuit will have four D-flipflops, one for each state.
The output of the circuit will be high when the sequence 0110 is detected.
The clock signal will be used to synchronize the flipflops.
The state diagram and circuit can be designed using software like Quartus or Xilinx.
Q35. 5 heads and two tails, separate into two groups such that two groups should have equal number of tails?
To separate 5 heads and 2 tails into two groups with equal number of tails, we can divide them as follows:
Group 1: 1 head and 1 tail
Group 2: 4 heads and 1 tail
Q36. Write a pseudo code to remove a node from a linked list
Pseudo code to remove a node from a linked list
Find the node to be removed
Update the previous node's next pointer to point to the next node
Free the memory occupied by the removed node
Q37. How do you obtain the in-phase and quadrature components of a real pass-band signal?
The in-phase and quadrature components of a real pass-band signal can be obtained using a complex mixer.
A complex mixer is used to convert the real pass-band signal to a complex baseband signal.
The in-phase component is obtained by multiplying the pass-band signal with a local oscillator signal in-phase with the carrier frequency.
The quadrature component is obtained by multiplying the pass-band signal with a local oscillator signal 90 degrees out of phase with the carrier fre...read more
Q38. How do you obtain the bit-rate for quantization of a band-limited signal?
The bit-rate for quantization of a band-limited signal can be obtained by considering the Nyquist-Shannon sampling theorem.
The Nyquist-Shannon sampling theorem states that in order to accurately represent a band-limited signal, the sampling rate must be at least twice the highest frequency component of the signal.
The bit-rate for quantization is determined by the number of bits used to represent each sample. It is typically calculated as the product of the sampling rate and t...read more
Q39. Explain the difference between Moore and Mealy state models
Moore state model outputs depend only on the current state, while Mealy state model outputs depend on both current state and inputs.
Moore model: output is a function of current state only
Mealy model: output is a function of current state and inputs
Moore model has a separate output function, while Mealy model combines output and state transition functions
Example: vending machine can be modeled using Mealy model as output depends on both current state and input (money inserted)...read more
Q40. Given a clock waveform of frequency f, design a circuit to get an output of frequency f/3
Design a circuit to get an output of frequency f/3 from a clock waveform of frequency f.
Use a counter to divide the frequency by 3
Implement a flip-flop to toggle the output
Use logic gates to control the counter and flip-flop
Q41. What is the difference between AC and DC?
AC and DC are two types of electrical current with different characteristics.
AC stands for Alternating Current, while DC stands for Direct Current.
AC periodically changes direction, while DC flows in one direction.
AC is commonly used in household electrical systems, while DC is used in batteries and electronic devices.
AC can be easily transformed to different voltage levels using transformers, while DC requires converters or inverters for voltage transformation.
AC is more eff...read more
Q42. How do you implement interpolation in discrete-time domain?
Interpolation in discrete-time domain involves estimating values between known data points.
Interpolation is used to fill in missing data or estimate values between known data points.
Common interpolation techniques include linear interpolation, polynomial interpolation, and spline interpolation.
Linear interpolation calculates values along a straight line between two known data points.
Polynomial interpolation uses a polynomial function to estimate values between data points.
Spl...read more
Q43. How much do you about Qualcomm ?
Qualcomm is a semiconductor and telecommunications equipment company based in San Diego, California.
Qualcomm is a leading provider of wireless technology and services.
They are known for their Snapdragon processors used in smartphones and other devices.
Qualcomm has been involved in several legal disputes with Apple and other companies over patent infringement.
They also have a strong presence in the development of 5G technology.
Qualcomm has a diverse portfolio of products and s...read more
1. What is Code Motion?
2. What are the different phases of compilation process?
3. Explain Lexical Analysis?
4. What are macros? What are inline functions?
5. What is recursion? Write a recursiv...read more
Q45. Arrange the inputs to AND gates so that power usage is optimized/delay is optimized
To optimize power usage/delay in AND gates, arrange inputs based on their capacitance and resistance.
Arrange inputs with lower capacitance and resistance closer to the gate
Inputs with higher capacitance and resistance should be placed farther away
Consider the layout of the circuit and the routing of the wires
Simulation tools can be used to determine optimal input arrangement
Q46. Draw the CMOS circuit for a given logic equation and do the corresponding W/L sizing
Answering a question on drawing CMOS circuit and W/L sizing for a given logic equation.
Understand the logic equation and its truth table
Use CMOS inverter and NAND gates to implement the logic
Size the transistors based on their role in the circuit
Check the circuit for correct functionality
Examples: AND gate, OR gate, XOR gate
Q47. Given the delays for gates and wires, draw output waveforms for the given logic circuit
Draw output waveforms for a logic circuit given delays for gates and wires.
Identify the logic gates and their delays
Determine the propagation delay for each wire
Use the delays to calculate the output waveform
Draw the waveform using a timing diagram
Q48. Obtain the Nyquist sampling frequency for an unevenly distributed band-limited signal.
Nyquist sampling frequency for unevenly distributed band-limited signal.
Determine the highest frequency component in the signal
Use Nyquist theorem to calculate the minimum sampling frequency
Sampling frequency should be at least twice the highest frequency component
Q49. What is modulation, and what are the different types of modulation schemes.
Modulation is the process of varying a carrier signal to transmit information. Different types include AM, FM, PM, and QAM.
Modulation is used to transfer information by varying a high-frequency carrier signal.
Amplitude Modulation (AM) varies the amplitude of the carrier signal to encode information.
Frequency Modulation (FM) varies the frequency of the carrier signal to encode information.
Phase Modulation (PM) varies the phase of the carrier signal to encode information.
Quadra...read more
Q50. Draw a circuit for a set of logic equations using PLA
A circuit for a set of logic equations using PLA
PLA stands for Programmable Logic Array
PLA is a type of digital circuit used to implement combinational logic circuits
The circuit consists of an AND array and an OR array
Inputs are fed into the AND array and the outputs are fed into the OR array
Example: A PLA circuit for a 2-input XOR gate would have 2 inputs, 2 AND gates, and 1 OR gate
Q51. Design a memory organization given the size and block units
Designing a memory organization based on size and block units.
Determine the size of the memory and the size of each block unit
Choose a suitable memory organization scheme such as direct mapping, associative mapping, or set-associative mapping
Implement the chosen scheme and test for efficiency and accuracy
Q52. Draw the circuit diagram for a random number generator
A random number generator circuit diagram can be created using a noise source and an amplifier.
Use a noise source such as a Zener diode or a reverse-biased transistor
Amplify the noise signal using an amplifier circuit
Use a comparator to convert the analog signal to a digital signal
Add a clock circuit to control the output frequency
Q53. How do you manage ISR ?
ISR stands for Interrupt Service Routine. It is managed by prioritizing interrupts and handling them in a timely manner.
Prioritize interrupts based on their importance
Handle interrupts in a timely manner to prevent delays in the system
Ensure that the ISR does not interfere with the normal flow of the program
Test the ISR thoroughly to ensure that it works as expected
Use appropriate tools and techniques to debug any issues that arise
Q54. how will you solve the disputes?
I will solve disputes by promoting open communication, active listening, and finding mutually beneficial solutions.
Encourage open and honest communication between parties involved
Actively listen to each party's concerns and perspectives
Identify common goals and interests to find mutually beneficial solutions
Mediate discussions and facilitate negotiations if necessary
Document agreements and ensure follow-up to prevent future disputes
Q55. Function to write data to some memory location which can dynamically allocate memory and return the address details where data is present .
Function to dynamically allocate memory and write data to a memory location, returning the address details.
Use malloc() or calloc() to dynamically allocate memory
Use memcpy() or strcpy() to write data to the allocated memory
Return the address details where data is present
Q56. Volatile usage w.r.t to gpio initialization, how volatile can help in overwriting compiler optimization.
Volatile keyword prevents compiler optimization by telling the compiler that the variable's value can change unexpectedly.
Volatile keyword is used to indicate that a variable may be changed unexpectedly, such as in the case of hardware registers.
When initializing GPIO pins, using volatile keyword ensures that the compiler does not optimize away the initialization code.
Without volatile keyword, the compiler may optimize out the GPIO initialization code if it thinks the value w...read more
Q57. Structure which can take input as 0 or 1 , based on the input traverse the linkedlist and return the decimal equivalent of the traversed data .
Traverse a linked list based on input 0 or 1 to return decimal equivalent.
Create a function that takes input 0 or 1 and traverses the linked list accordingly.
For each node in the linked list, multiply the current decimal value by 2 and add the data of the node if input is 1.
Return the final decimal value after traversing the linked list.
Q58. In real time operating systems which scheduling strategy will you choose?
The choice of scheduling strategy in real-time operating systems depends on the system requirements and constraints.
Priority-based scheduling is commonly used in real-time operating systems.
Earliest Deadline First (EDF) scheduling is suitable for systems with strict deadlines.
Rate Monotonic Scheduling (RMS) is appropriate for systems with periodic tasks.
Shortest Job First (SJF) scheduling can be used for systems with non-periodic tasks.
The choice of scheduling strategy should...read more
Q59. what is the complexity of quick sort?
Quick sort has an average and worst-case time complexity of O(n log n).
Quick sort is a divide-and-conquer algorithm.
It selects a pivot element and partitions the array around the pivot.
The average and worst-case time complexity is O(n log n).
However, in the worst-case scenario, it can have a time complexity of O(n^2).
Q60. what is your view about Qualcomm?
Qualcomm is a leading semiconductor and telecommunications equipment company.
Qualcomm is known for its expertise in wireless technologies and mobile chipsets.
They have developed popular Snapdragon processors used in smartphones and tablets.
Qualcomm has made significant contributions to the advancement of 5G technology.
The company has a strong patent portfolio and is involved in licensing its technology to other manufacturers.
Qualcomm has faced legal challenges and regulatory ...read more
1. What is an interrupt?
2. How are interrupts handled? Explain with an example.
3. How ISR works? What happens when an interrupt is raised?
4. Is there any table involved in the whole proc...read more
Q62. Where can you different types analog modulation schemes?
Different types of analog modulation schemes can be found in various communication systems.
Analog modulation schemes are used in radio broadcasting, television transmission, and wireless communication.
Some common types of analog modulation schemes include amplitude modulation (AM), frequency modulation (FM), and phase modulation (PM).
AM is used in AM radio broadcasting, where the amplitude of the carrier signal is varied to transmit audio signals.
FM is used in FM radio broadc...read more
Q63. you have various strings each associated with an arbitrary 32-bit integer.what data structure will you choose if you need to search for a string given its number?
Use a hash table to store the strings with their associated integers.
Create a hash table with the integers as keys and the strings as values.
Use a hash function to map the integers to their corresponding buckets in the table.
To search for a string, compute the hash of its associated integer and look it up in the table.
Q64. hy do we have two modes of execution in operating systems?what are they?
Two modes of execution in operating systems are user mode and kernel mode.
User mode is a restricted mode where user applications run.
Kernel mode is a privileged mode where the operating system kernel runs.
User mode has limited access to hardware and system resources.
Kernel mode has full access to hardware and system resources.
Switching between modes requires a system call or interrupt.
Examples of system calls include opening a file or creating a process.
Kernel mode is more po...read more
Q65. Why linux kernel ? And About how to compile linux kernel?
Linux kernel is popular for its open-source nature, stability, security, and flexibility. Compiling it allows customization and optimization.
Linux kernel is widely used due to its open-source nature, allowing for customization and collaboration.
It is known for its stability, security, and flexibility, making it a preferred choice for many developers and organizations.
Compiling the Linux kernel involves configuring the kernel options, building the kernel image, and installing ...read more
Q66. write a program with 2 threads. one thread should print even and other should print odd numbers in sequence. how would you make it SMP safe?
Program with 2 threads printing even and odd numbers in sequence. How to make it SMP safe?
Use mutex locks to ensure only one thread accesses the shared resource (the number to be printed) at a time
Use condition variables to signal when it's safe for the other thread to access the shared resource
Use atomic variables to ensure that the shared resource is accessed atomically
Use thread-safe data structures to store the shared resource
Use thread-local storage to avoid contention b...read more
Q67. What is the propagation delay in Electromagnetic wave?
Propagation delay is the time it takes for an electromagnetic wave to travel from one point to another.
Propagation delay is determined by the distance between the two points and the speed of light.
It is the time it takes for the wave to propagate through a medium or free space.
Propagation delay can be calculated using the formula: delay = distance / speed of light.
For example, if the distance between two points is 100 meters, and the speed of light is 3 x 10^8 meters per seco...read more
Q68. What happens at stack/memory level when a null ptr is dereferenced?
When a null pointer is dereferenced, it leads to a segmentation fault or access violation, causing the program to crash.
Dereferencing a null pointer means trying to access the memory location pointed by the null pointer.
This results in a segmentation fault or access violation, as the null pointer does not point to a valid memory address.
The operating system detects the illegal memory access and terminates the program to prevent further issues.
The stack and memory remain unaff...read more
Q69. what is alternator and generator?
An alternator and generator are devices that convert mechanical energy into electrical energy.
Both alternators and generators are used to generate electricity.
They work on the principle of electromagnetic induction.
Alternators are commonly used in modern vehicles to charge the battery and power the electrical systems.
Generators are often used as backup power sources during power outages.
Examples of alternators include those found in cars, motorcycles, and airplanes.
Examples o...read more
Q70. Y c malloc function returns and y stack operates in reverse
The y c malloc function returns memory from the heap while y stack operates in reverse.
The y c malloc function is used to allocate memory dynamically from the heap.
The y stack operates in reverse, meaning the last item pushed onto the stack is the first item popped off.
This can cause issues if the programmer is not careful with memory allocation and stack usage.
Q71. What is a Schmitt trigger/inverter?
A Schmitt trigger/inverter is a circuit that converts a noisy input signal into a clean digital output signal.
It has two threshold voltage levels: a high threshold and a low threshold
The output of the circuit changes state only when the input voltage crosses one of the threshold levels
It is commonly used in digital circuits to clean up noisy signals and to provide hysteresis
Examples include debouncing switches, signal conditioning, and waveform shaping
Q72. what are the types of caching mechanisms?
Types of caching mechanisms include browser caching, server-side caching, and content delivery network (CDN) caching.
Browser caching: storing web page resources locally on a user's device to reduce load times on subsequent visits.
Server-side caching: storing data in memory on the server to reduce the need to fetch data from the database repeatedly.
Content Delivery Network (CDN) caching: caching content on servers distributed geographically to reduce latency and improve perfor...read more
Then he asked if two or more processes want to access the same resource. What can happen?
What is a Semaphore? How it can be implemented? He made me to write the codes for implementation.
Q75. Mock code to initialize gpio using hal functions as well as write a function to set and clear gpio status .
Initialize and control GPIO using HAL functions in embedded systems.
Use HAL_GPIO_Init() function to initialize GPIO pins
Use HAL_GPIO_WritePin() function to set or clear GPIO status
Example: HAL_GPIO_Init(&GPIO_InitStruct)
Example: HAL_GPIO_WritePin(GPIOx, GPIO_PIN_x, GPIO_PIN_SET)
Q76. How does the frequency spectrum change if alternate samples in the time domain are negated?
Negating alternate samples in time domain results in spectral inversion.
Negating alternate samples in time domain is equivalent to multiplying the signal by a square wave with alternating values of +1 and -1.
This multiplication in time domain results in spectral convolution in frequency domain.
The frequency spectrum is inverted around the Nyquist frequency due to the spectral convolution.
This technique is used in some audio effects like flangers and phasers.
It can also be use...read more
Q77. What is VSWR and what is the need for it?
VSWR stands for Voltage Standing Wave Ratio. It is a measure of how well a transmission line is matched to the impedance of the connected devices.
VSWR is a ratio of the maximum voltage to the minimum voltage along a transmission line.
It is used to measure the efficiency of power transfer and the impedance matching in RF systems.
A lower VSWR indicates better impedance matching and less power loss.
VSWR is important in RF systems to prevent signal reflections, which can degrade ...read more
Q78. What is a standing wave in a transmission line?
A standing wave in a transmission line is a wave that appears to be stationary, resulting from the interference of two waves traveling in opposite directions.
A standing wave is formed when a wave traveling in one direction reflects back upon encountering an impedance mismatch in the transmission line.
The interference between the incident and reflected waves creates regions of constructive and destructive interference, resulting in nodes and antinodes along the transmission li...read more
Semaphores, Mutex, Synchronisation etc.
Q80. What is histogram equilization. What does it do to the probability distribution of pixels?
Histogram equalization is a technique to enhance the contrast of an image by redistributing pixel intensities.
Histogram equalization stretches the histogram of an image to cover the entire range of pixel values.
It increases the dynamic range of an image, making it visually more appealing.
It improves the visibility of details in both dark and bright regions of an image.
Histogram equalization can be used to enhance images with low contrast or uneven lighting conditions.
For exam...read more
Q81. How many parallelograms are there in a grid of mxn parallel lines?
Q82. what topology do you have in your LAB and why?
My LAB has a star topology because it provides centralized control and easy troubleshooting.
Star topology has a central hub that connects all devices
All communication goes through the hub
Easy to add or remove devices without affecting the rest of the network
Commonly used in LANs
Examples: Home networks, small businesses
Q83. Imagine an attack and guide through all steps involved to determine a Risk value. What is Feasibility ? What is impact and how risk is related to these factors ?
Feasibility, impact, and risk are key factors in determining the risk value of an attack.
Feasibility refers to how likely an attack is to occur based on the resources and knowledge required.
Impact measures the potential damage or consequences of the attack if successful.
Risk is the combination of feasibility and impact, representing the likelihood and severity of the attack.
To determine risk value, assess the feasibility of the attack based on available vulnerabilities, then ...read more
Q84. In ISO21434 what is distributed cybersecurity activities?
Distributed cybersecurity activities in ISO21434 refer to the implementation of cybersecurity measures across multiple components or systems within a network.
Distributed cybersecurity activities involve securing various interconnected components or systems within a network.
This includes implementing security measures such as firewalls, encryption, access controls, and intrusion detection systems.
The goal is to protect the entire network from cyber threats by addressing vulner...read more
Q85. What is mutex ?
Mutex is a synchronization mechanism used to prevent multiple threads from accessing shared resources simultaneously.
Mutex stands for mutual exclusion.
It is used to protect shared resources from race conditions.
Mutex provides exclusive access to a shared resource.
It is used in multi-threaded programming.
Mutex can be implemented using locks or semaphores.
Q86. How do you construct a 4x16 decoder from 2x4 decoders with enable pins
Q87. write full and working code to sort a linked list with minimum time complexity
Sort a linked list with minimum time complexity
Use merge sort or quick sort for O(n log n) time complexity
Implement the sorting algorithm recursively
Use a temporary linked list to merge the sorted sub-lists
Consider edge cases like empty list or list with only one element
Q88. write a code to print all the connected components in a graph.
Code to print all connected components in a graph.
Implement Depth First Search (DFS) algorithm to traverse the graph.
Maintain a visited array to keep track of visited nodes.
For each unvisited node, perform DFS and add all visited nodes to a connected component.
Repeat until all nodes are visited.
Print all connected components.
What's an OS, Various OS services. What OS manages and how?
Q90. What is the distribution of product of N normal RVs
The product of N normal RVs is a non-central chi-squared distribution with N degrees of freedom.
The distribution is non-central chi-squared with N degrees of freedom
The non-centrality parameter is the product of the means of the RVs
The variance of the distribution is the product of the variances of the RVs
This distribution is commonly used in signal processing and communication systems
Q91. Draw waveforms of Amplitude and FM/PM modulation scheme?
Amplitude modulation (AM) and frequency modulation (FM) waveforms can be represented graphically.
AM modulation: The amplitude of the carrier signal is varied in proportion to the amplitude of the modulating signal.
FM modulation: The frequency of the carrier signal is varied in proportion to the amplitude of the modulating signal.
Waveforms can be drawn to show the variations in amplitude or frequency over time.
AM waveform will have varying amplitudes while FM waveform will hav...read more
Q92. How would you know .. your system is little endian or big endian??
Endianess refers to the order in which bytes are stored in memory. Little endian stores the least significant byte first.
Check the byte order of a multi-byte integer value
Use a test value with known byte order to determine the system's endianess
Check the system's documentation or specifications
Use a code snippet to determine the endianess
Q93. Build a function that returns the Fibonacci series of N elements
Function to return Fibonacci series of N elements
Create an array to store the series
Use a loop to generate the series
Return the array
Q94. how a function from one user process can be called in other user process?
Inter-process communication mechanisms like pipes, sockets, message queues, shared memory can be used to call a function from one user process to another.
Use pipes to establish a unidirectional communication channel between two processes.
Use sockets to establish a bidirectional communication channel between two processes.
Use message queues to send messages between processes.
Use shared memory to share data between processes.
Remote Procedure Call (RPC) can also be used to call ...read more
What is a TSL? How locks can be implemented in OS?
Q96. fill the cells in the pyramid?
Fill the cells in the pyramid
The pyramid is a pattern of numbers or characters arranged in a triangular shape
Each row of the pyramid has one more cell than the previous row
Start filling the pyramid from the top and move downwards
The cells can be filled with any desired numbers or characters
Q97. Maximal Ratio Combining in MIMO, Quantization Noise power
Maximal Ratio Combining (MRC) is a technique used in MIMO systems to improve signal quality by combining multiple received signals.
MRC combines the received signals from multiple antennas to maximize the signal-to-noise ratio (SNR)
Quantization noise power refers to the noise introduced during the process of converting analog signals to digital signals
In MIMO systems, MRC can be used to mitigate the effects of quantization noise
MRC calculates the weights for each received sign...read more
Q98. Program to find length of bits assigned in memory using recursion.
Program to find length of bits assigned in memory using recursion.
Define a recursive function to count the bits in memory
Base case: if input is 0, return 0
Recursive case: return 1 + function(input / 2)
Q99. Program to find the sum of all the digital in the number .
Program to find the sum of all the digits in a number.
Iterate through each digit in the number and add them together.
Convert the number to a string to easily access each digit.
Use modulo operator to extract each digit from the number.
Handle negative numbers by taking the absolute value before processing.
Q100. Create a linkedlist check if list is circular if not then reverse it .
Check if a linked list is circular, if not reverse it.
Create two pointers, one moving at double the speed of the other to detect a cycle
If a cycle is detected, the list is circular. If not, reverse the list by changing the pointers' directions
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