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This is for DSP Position phone interview Today I got phone interviewed for the DSP team. The scheduled time was 30 min, it went to about 50min, mostly because I talked too much, which is not very good thing. The first half an hour, he asked me a lot of questions on my resume 1. How did you port rtos? 2. what was the precise timing control? 3. How did you improve FFT? ... In the second part he was focused on comm and dsp concepts, how to implement a FIR how to implement a filter with FFT? if PLL has statibily issue, where to look? Cell phone power control down to the radio power and already in the min power, how to reduce the interference to others? In signal space, the modulated signal got closer and closer, how to get better demodulation?
avatar

Firmware Engineer

Interviewed at Qualcomm

3.8★
May 7, 2011

This is for DSP Position phone interview Today I got phone interviewed for the DSP team. The scheduled time was 30 min, it went to about 50min, mostly because I talked too much, which is not very good thing. The first half an hour, he asked me a lot of questions on my resume 1. How did you port rtos? 2. what was the precise timing control? 3. How did you improve FFT? ... In the second part he was focused on comm and dsp concepts, how to implement a FIR how to implement a filter with FFT? if PLL has statibily issue, where to look? Cell phone power control down to the radio power and already in the min power, how to reduce the interference to others? In signal space, the modulated signal got closer and closer, how to get better demodulation?

Most questions would be based on your resume. They will concetrate what you did and not what they did :). So, please know in & out about your resume. Also, Please do not stuff your resume just for the sake of getting an interview call. Even if it did, it may be an issue if you did not answer their question on that topic. It is better to put stuff on which you are confident. For me, most of my telephonic interview had questions from Wireless Communications, Digital Communications, Random Signal Theory(Not in depth, for ex: How is a wireless channel distributed? why is it distributed like that? How does it's auto-correlation looks like? what are the other models available? Suggestions: Be good in Wireless Communications: Multipath, Coherence time, coherence bandwidth, time diversity, receiver diversity, doppler spread, WSS-US model, Rayleigh Fading, Rician Fading, Diversity schemes, Equalizers, OFDM, and the projects related to it. Digital Communication: Modulation schemes, BER, Basic Communication block diagram, etc. Last, but not least, in all these interviews there is no one-on-one answer. So, knowing the definitions related to this topics will not help. Try to related and study. A simple question, I would like to quote here, to say, how will their expectation be like. For Ex: Compare OFDM and CDMA. Hint you have is: With Shannon's channel thm, try to explain this. So, the interviewer is expecting you to apply a concept to two different technologies. Ex: Next question: How OFDM mitigates ISI? How CDMA mititgates ISI. (You must give an in-depth idea) Ex: Match Filters. How CDMA uses it. (Please go through match filter in-depth. This idea is used in CDMA Rake Reception. Please know, how it is getting used there. Also, Match filtering, is a kind of process that you can use for Channel estimation. Knowing the call processing procedure for any technology will also help. Please ,be sure with atleast one technology in depth. Last Suggestion: When the interviewer asks a question on a topic that you know well, start answering him that question with depth, so that your further questions will be based on it. So, this is like driving interviewer to an area that you are familiar. Else, it will be like he is trying to ask you different questions to know what you know. Best!
avatar

Modem Firmware Test Engineer

Interviewed at Qualcomm

3.8★
Mar 19, 2013

Most questions would be based on your resume. They will concetrate what you did and not what they did :). So, please know in & out about your resume. Also, Please do not stuff your resume just for the sake of getting an interview call. Even if it did, it may be an issue if you did not answer their question on that topic. It is better to put stuff on which you are confident. For me, most of my telephonic interview had questions from Wireless Communications, Digital Communications, Random Signal Theory(Not in depth, for ex: How is a wireless channel distributed? why is it distributed like that? How does it's auto-correlation looks like? what are the other models available? Suggestions: Be good in Wireless Communications: Multipath, Coherence time, coherence bandwidth, time diversity, receiver diversity, doppler spread, WSS-US model, Rayleigh Fading, Rician Fading, Diversity schemes, Equalizers, OFDM, and the projects related to it. Digital Communication: Modulation schemes, BER, Basic Communication block diagram, etc. Last, but not least, in all these interviews there is no one-on-one answer. So, knowing the definitions related to this topics will not help. Try to related and study. A simple question, I would like to quote here, to say, how will their expectation be like. For Ex: Compare OFDM and CDMA. Hint you have is: With Shannon's channel thm, try to explain this. So, the interviewer is expecting you to apply a concept to two different technologies. Ex: Next question: How OFDM mitigates ISI? How CDMA mititgates ISI. (You must give an in-depth idea) Ex: Match Filters. How CDMA uses it. (Please go through match filter in-depth. This idea is used in CDMA Rake Reception. Please know, how it is getting used there. Also, Match filtering, is a kind of process that you can use for Channel estimation. Knowing the call processing procedure for any technology will also help. Please ,be sure with atleast one technology in depth. Last Suggestion: When the interviewer asks a question on a topic that you know well, start answering him that question with depth, so that your further questions will be based on it. So, this is like driving interviewer to an area that you are familiar. Else, it will be like he is trying to ask you different questions to know what you know. Best!

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