Dsp Engineer Interview Questions
209
Dsp Engineer interview questions shared by candidates
Write a c functions that takes two bit indices and an int, and reverses the bits in the int between the two indices.
9 Answers↳
Made no mistakes on this question, but had done similar things before
↳
//reverses bit between two indices of a number. #include using namespace std; int main() { unsigned int no=90,i=2,j=6,tmp=0,tmp1=0; tmp=no>>i; cout>1; } cout>1; if(x=i) tmp=tmp|0; else tmp=tmp|0x80000000; } cout< Less
↳
#include main(int arg, char *argv[]) { unsigned char num, hi_indx, lo_indx, mask, num_tmp, mask_c, num_rv, iter,i; num = atoi(argv[1]); hi_indx = atoi(argv[2]); lo_indx = atoi(argv[3]); mask = ((0xFF > (7-hi_indx+lo_indx); mask = (mask << lo_indx); mask_c = ~mask; num_tmp = num & mask_c; printf("%x %d %d %x",num, hi_indx, lo_indx, mask); num_rv = 0x0; iter = hi_indx-lo_indx+1; i = 0; while(i<=iter) { int flg; flg=(num & (1<<(i+lo_indx)))?1:0; if(flg) num_rv=num_rv|(1<<(hi_indx-i)); i++; } num = num_rv | num_tmp; printf("\nnum=%x ",num); } Less
What is the Z-transform of y[n] = x[n] + 2x[n-1]?
2 Answers↳
I realized this wasn't this job for me. I didn't study EE and the headhunter should have seen that. Yes I have a PhD in psychoacoustics and have done a fair amount of programming of filters and frequency domain analysis, but my theoretical knowledge is (extremely) minimal. 30 minutes after the interview and remembering that x[n-1] = z^-1, and then revisiting the textbook, I realized that the z-transform is indeed 1 + 2z^-1. *This would have been a very easy interview for someone with a BSEE.* Less
↳
1/(1+2z^-1)
qtns abt OFDM, qtns abt cyclic prefix, qtns abt wideband channel, qtns abt block convolution: overlap save
1 Answers↳
These qtns where to test the DSP, Communication Theory background.
Explain OFDM, Viterbi algorithm, Write Linked List algorithm in C on board...
1 Answers↳
OFDM - Orthogonal Frequency Division Multiplexing. This is a multi-carrier modulation scheme, where the data is transmitted as large amount of orthogonal sub-carriers on parallel data streams. Since they are orthogonal, they do not affect each other sub-carrier. Each sub-carrier is modulated using QAM/PSK. This is very efficient when used with MIMO and in DSL systems. Less
how many beamformers are possible for a given number of antennas
1 Answers↳
Ideally you can have as many beamformers as you can, but you need to reduce the number for practical applications. There is no specific formula. However they expect a fixed number. Seems they are just academic theoretical knowledge with no practical experience. Less
I first round they asked me about the project in very much detail and they interested in my EEG signal based project and were trying to get the whole idea to do it.
1 Answers↳
I answered the feature extraction and dsp based techniques to create new features and machine learning algorithm to classify those signals. Less
Why use Polyphase filters for decimation and interpolation
1 Answers↳
To reduce complexity of resampling through different stages