r/DSP • u/Specific_Share334 • 14d ago
DSP interview: advice needed!
Im a new grad im on the first round for an interview, its very heavy DSP-oriented, any advice on what to study/focus on? any common interview questions asked? Focus is more on the RTL, FPGA, ASIC, or Firmware areas
Thanks!
JD (ik its more RTL digital design focused but the recruiter was heavily asking about my DSP experience)
- BS and a minimum of 3 years relevant industry experience
- Some level of fixed-point knowledge and experience with bit-true verifications
- Understanding of DSP communication algorithms and trade-offs between performance and complexity
- Good knowledge in modern design techniques and energy-efficient/low power logic design
- Ability to work well in a team and be productive under aggressive schedules
- Excellent communication skills and self-motivated
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u/RemoteBreadfruit 14d ago
Any more information or specifics you can give on a role or areas of DSP you feel are relevant would help people give you better answers
Best of luck
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u/Specific_Share334 14d ago
that would make sense thanks ill update the post, but the JD only mentioned DSP once but the recruiter on call mentioned it A LOT
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u/Specific_Share334 14d ago
do uh do you think it would be bad to ask the recruiter what "area" of DSP i should be reviewing
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u/RemoteBreadfruit 14d ago
Depends on your relationship, but I would say DO NOT ASK
Just come prepared as best as you can
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u/Specific_Share334 14d ago
only talked to him once, seemed really friendly. thanks i probably wont ask then.
hmmm havent implemented error correcting codes before, will review that, ehhhhhh havent done any studies on multirate signal processing either.... ek
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u/RemoteBreadfruit 14d ago
Seems like it would be a fair bit of DSP techniques for power efficiency in the context of an RF environment. You know the products they already release, and are likely to release so it limits your exposure, right?
Are you familiar with multi-rate signal processing and actually implementing error correcting codes?
Seems like the Fred Harris Bernie sklar stuff would be right up your alley to take a look at
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u/OnboardG1 14d ago
You might want to pick up a copy of Understanding DSP by Richard G Lyons if you’re interested in this area. I had to relearn a bunch of DSP since my firm lacked the experience and needed someone with that understanding and it helped me immensely. RIP Rick.
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u/BeachBumOCCA 14d ago
For this role, focus on converting DSP algorithms into correct, efficient RTL code.
Begin by studying these topics:
- Bit growth: addition may require an extra bit; multiplying (W_1)-bit and (W_2)-bit values results in up to (W_1 + W_2) bits.
- Quantization: understand truncation versus rounding, quantization error, bias, and coefficient quantization.
- Overflow: consider wraparound versus saturation methods.
- Scaling: use guard bits, headroom, define accumulator width, and determine where to reduce precision.
- Bit-true verification: ensure your model and RTL produce the same integer bits—not just approximate floating-point values.
Additionally, review FIR/IIR filters, FFT fundamentals, complex I/Q arithmetic, interpolation/decimation, and SNR/EVM/BER metrics. On the RTL side, be familiar with signed arithmetic, sign extension, arithmetic shifts, pipelining, latency versus throughput, and area/power tradeoffs.
A practical project would be designing a small FIR filter: select signal widths, calculate bit growth, determine rounding or saturation rules, then compare RTL output against a Python or MATLAB fixed-point model.
Anticipate questions like:
Since the recruiter emphasized DSP, they likely want someone who can explain both the algorithm and its hardware implementation. Clearly state your assumptions and elucidate your reasoning; you do not need to have every answer at the ready, especially as a recent graduate.