## Forums

## Sample Rate of a Digital Audio Delivery Medium (i.e., CD)

inPerhaps I'm forgetting something, but why would the sample rate of the digital audio delivery medium such as CD have _anything_ to do with...

Perhaps I'm forgetting something, but why would the sample rate of the digital audio delivery medium such as CD have _anything_ to do with the ease of sampling the original signal? It is certainly true that it is better to oversample the original analog input so that the antialiasing filter requirements can be greatly relaxed. However, once we're in the digital domain we can run some very ...

## Which frequency for PWM in motor control?

inMy understanding is that within the audible frequencies - we don't like the annoying sound for starters and for higher frequencies the ripple is...

My understanding is that within the audible frequencies - we don't like the annoying sound for starters and for higher frequencies the ripple is less (for current in the motor). Disadvantage is that faster switching in the MOSFETs make then hotter. One more thing - does operating at a low a frequency PWM frequency in a control loop introduce phase-lag?

## Matched Filter Vs Correlator Receiver

inProakis seems to want to differentiate between these two architectures. What's the difference? Whether you integrate the output of f(t)r(t),...

Proakis seems to want to differentiate between these two architectures. What's the difference? Whether you integrate the output of f(t)r(t), or input r(t) into a filter with impulse response f(-t+T), it's all the same. No? -- % Randy Yates % "Watching all the days go by... %% Fuquay-Varina, NC % Who are you and who am I?" %%% 919-577-9882 ...

## 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? -- ...

## what matrices are easiest to invert?

inSimultaneous equations with random coefficients go through Gaussian elimination - awfully slow if you have 100+ rows. I know Toeplitz,...

Simultaneous equations with random coefficients go through Gaussian elimination - awfully slow if you have 100+ rows. I know Toeplitz, tridiagonal and pentadiagonal have special solutions that are much faster. Any other matrix that has a more efficient algorithm to solve?

## 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

## 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

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