## Forums comp.dsp

## Integrate PDM to PCM?

inAs a bat call recording enthusiast I'd like to use a pair of digital MEMS elements whose ultrasonic performance appears to be well suited. The...

As a bat call recording enthusiast I'd like to use a pair of digital MEMS elements whose ultrasonic performance appears to be well suited. The Knowles SPH0641LM4H-1 mic output is PDM and can run at 4.8MHz. I want to stay in digital domain, ultimately recording 16-bit PCM at 192kHz. Researching PDM-to-PCM conversion algorithms suggests low-pass filtering. Analog's ADAU7002Z PDM to

## Injecting a complex frequency

insuppose I have a stable analogue system (no feedback - open loop) with two complex poles only. If I take the frequency response it will have a...

suppose I have a stable analogue system (no feedback - open loop) with two complex poles only. If I take the frequency response it will have a small overshoot in the frequency domain but the gain does not go to infinity because the pole(s) are not on the jw axis. Is it possible to excite the same system with a complex signal sigma+jw so that you excit the stable pole. ie normally fr

## Quadrature Signals: Complex but Not Complicated

inHey Eric, The dspguru link to Rick's article "Quadrature Signals: Complex but Not Complicated" ...

Hey Eric, The dspguru link to Rick's article "Quadrature Signals: Complex but Not Complicated" http://www.dspguru.com/info/tutor/QuadSignals.pdf you provided in a reference in your dsprelated article "Handling Spectral Inversion in Baseband Processing" https://www.dsprelated.com/showarticle/51.php doesn't work for me. It reports "Page not found." Is there an alternate? -- ...

## definition of semblance (and similar functions)?

Consider multi-channel data. You have a 2D array. To compute semblance at a given time, divide the square of sum of the samples at said time by...

Consider multi-channel data. You have a 2D array. To compute semblance at a given time, divide the square of sum of the samples at said time by sum of the squares of those samples. So if all the peaks line up you get maximum semblance. Now I came across some code that computed the absolute value of the sum of the samples divided by the sum of the absolute values, and the concoctor was callin...

## Fractional Fourier Transform

inHello The Fourier Transform decomposes a function of time (a signal) into the frequencies, and it's inverse transform means that a time domain...

Hello The Fourier Transform decomposes a function of time (a signal) into the frequencies, and it's inverse transform means that a time domain signal can be constructed as a sum of trigonometric sinusoidal functions. I am now also trying to understand and visualize the Fractional Fourier Transform (FrFT). I am actually new in this topic and have found some usefull articles regarding FrFT o...

## Nakagami -m Noise

inHi everyone, i was working with AWG noise and now i have to move to nakagami-m noise, is there a simple and clear formula that i can use to...

Hi everyone, i was working with AWG noise and now i have to move to nakagami-m noise, is there a simple and clear formula that i can use to calculate some variables like capacity or SNR. i only found a closed form based on pdf, i didn't know how to use it for system capacity calculation. can anyone help with some references or explanation please. Thank you in advance

## Off-Topic : Looking for IP camera which can send audio via RTP to remote client

inI am looking for an IP camera that: 1. will allow me to programmatically connect to it (over UDP or TCP) 2. will send me the camera's...

I am looking for an IP camera that: 1. will allow me to programmatically connect to it (over UDP or TCP) 2. will send me the camera's microphone audio as RTP over UDP 3. supports the following audio sample rates: 8000Hz and any sample rate greater than or equal to 44.1kHz Any recommendations?

## Looking for the whitest sequence of 1's and 0's

inNo, I'm not suddenly turning racist -- this is about signal processing. I want to fill a vector with binary numbers, evenly balanced between...

No, I'm not suddenly turning racist -- this is about signal processing. I want to fill a vector with binary numbers, evenly balanced between ones and zeros, such that (with the exception of the honkin' big spike at DC) its FFT is as flat as possible. Is there an algorithm for doing this? -- Tim Wescott Wescott Design Services http://www.wescottdesign.com I'm looking for work ...

## Two questions about differential and difference equations

inI'm working on an instructional video, and while I don't mind tossing out some hand-waving, and even some minor inaccuracies, I don't want to...

I'm working on an instructional video, and while I don't mind tossing out some hand-waving, and even some minor inaccuracies, I don't want to get things ENTIRELY wrong. First question: Quite a while ago, quite by accident, I discovered that one could solve linear shift-invariant difference equations via "the hard way" in much the same way that one solved linear differential equations...

## Cascading FIR

inHello I have two DSP connected in serial mode. Have FIR with 2000 coefficients . Need to recalc and divide coefficients of FIR by 1000 for 2...

Hello I have two DSP connected in serial mode. Have FIR with 2000 coefficients . Need to recalc and divide coefficients of FIR by 1000 for 2 DSP, so that in serial application give result of FIR with 2000 points. Delay of FIR here dont work, bcs FIR of each DSP is 1000 points maximum. Is this possible? WBR, Vasilius. --------------------------------------- Posted through http://...

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