Forums More Forums
FFT zero analyzing pink noise
inIm doing the pink noise FFT. I calculate the frequency of 1kHz by adding the contribution of the corresponding bins. Is it possible that sometimes...
Im doing the pink noise FFT. I calculate the frequency of 1kHz by adding the contribution of the corresponding bins. Is it possible that sometimes the result is zero? Thanks.
5-point stencil or Savitsky-Golay for differences
inI had some code computing the second difference of a sampled signal as (x(n-1)-2x(n)+x(n+1))/(square of interval) I only needed a crude estimate...
I had some code computing the second difference of a sampled signal as (x(n-1)-2x(n)+x(n+1))/(square of interval) I only needed a crude estimate of the second derivative in this case. Then I came across "five point stencils" By this method, the second difference is (-x(n-2)+16x(n-1)-30n(n)+16x(n+1)-x(n+2))/12/(square of interval) And then 5-sample Savitsky-Golay formula, which seems rath...
Power Ratios?
inI'm confused by some code I wrote to measure signal amplitude from a CODEC. The FPGA sampled for some period of time squaring the samples and...
I'm confused by some code I wrote to measure signal amplitude from a CODEC. The FPGA sampled for some period of time squaring the samples and summing them up. I did not take the square root of the result, at least not in the FPGA. I would expect this result to be proportional to the power in the signal. When I compare this number at multiple frequencies to get the variations,
Correlation Versus Simple Filter
inGentle Readers, Ok, I've been out of DSP for way too long so maybe this is a stupid question, but in the interest of getting my feet wet...
Gentle Readers, Ok, I've been out of DSP for way too long so maybe this is a stupid question, but in the interest of getting my feet wet again, here goes. Let's say we have a tone which we want to detect. Which is going to give better performance, correlation followed by a threshold or a simple bandpass filter followed by an energy detector and threshold? -- Randy Yates, DSP/Embedded ...
Ultrasonic speech
inA client for unknown reasons wants to emit speech in teh frequency range above 20kHz. I was wondering what is the best way around this to do a...
A client for unknown reasons wants to emit speech in teh frequency range above 20kHz. I was wondering what is the best way around this to do a frequency shift. Then presumably I would need a sound card on a PC with high sampling rate and ultrasonic amplifier and loudspeaker. (this can be bought). So I sample at say 44.1KHz as usual a section of speech and store to wav file. Then I
Elwyn Berlekamp RIP
inA few of us had the great fortune to work with Elwyn Berlekamp during our careers. He passed away on April 9, 2019. The most prolific and...
A few of us had the great fortune to work with Elwyn Berlekamp during our careers. He passed away on April 9, 2019. The most prolific and most genius expert on algebraic coding, Berlekamp also contributed significantly to game theory, cryptology, and quant. He was a member of the USA National Academies of both Engineering and Science, recipient of both the Shannon Award and the Hamming M...
Homodyne complex frequency shift
inHi, the input signal is sin(t), I multiply it with cos(t) to get the I component and sin(t) to get the Q component. So...
Hi, the input signal is sin(t), I multiply it with cos(t) to get the I component and sin(t) to get the Q component. So then I(t)=sin(t)*cos(t)=0.5*sin(2t) Q(t)=sin(t)^2 I would expect only the DC component to persist, but instead I have two quickly wiggling waves. What is missing to shift 1kHz to DC without introducing the mirror frequencies? Thanks in advance!
Multiple PDM mic recording
How to record multiple PDM mics at 16KHz? What is a recommended soundcard/HW that can be used?
How to record multiple PDM mics at 16KHz? What is a recommended soundcard/HW that can be used?
Threshold of hearing compensation
inThere are several new consumer headphone products on the market that allow you to measure your threshold of hearing using an app on your phone and...
There are several new consumer headphone products on the market that allow you to measure your threshold of hearing using an app on your phone and then auto-adjust an equalizer to boost the areas where your threshold is high (indicating hearing loss at those frequencies). Iâm no audiologist but this seems suspicious to me; I donât think having a high threshold is the
short pulse generation with DSK6416
inHello, I'm trying to generate short pulses with DSP's 32-bit timer. I'm using the DSK6416 board (@1GHz) . I need to have pulse widths as...
Hello, I'm trying to generate short pulses with DSP's 32-bit timer. I'm using the DSK6416 board (@1GHz) . I need to have pulse widths as short as 10ns-50ns and be able to change the duty-cycle. I try to read the CNT register of the timer and set DATOUT to be driven on TOUT pin of timer when the proper width has reached. The problem is that when I use the TIMER_setDatOut API it is not possible...
Ask a Question to the DSPRelated community
To significantly increase your chances of receiving answers, please make sure to:
- Use a meaningful title
- Express your question clearly and well
- Do not use this forum to promote your product, service or business
- Write in clear, grammatical, correctly-spelled language
- Do not post content that violates a copyright