the issue for feedback cell and compressor cell
Thread Summary
The user asks about initializing a feedback cell for a recursive formula y(n)=x(n)+y(n-1) with y(0)=1.0 and the threshold and ratio steps in a compressor module. The final answer indicates that data flow values start at zero and cannot be easily initialized, and the compressor GUI calculates 33 table points for the DSP, with the threshold step appearing to be 0.1 dB and the ratio step varying. The user is directed to a detailed compressor table format document for further configuration.AI Generated Content
Two questions:
1) How to set the initial value for feedback cell? according to help, feedback cell is a sample delay. when i need calculate the formula like this
y(n)=x(n)+y(n-1), y(0)=1.0, is it correct using feedback cell? if i use delay cell, it seems that user cann't write DATA RAM, then how i set this
initial value y(0)=1.0 ?
2) whens i use the compressor module, i confuse the step of threshold and compressor ratio.
for example:
threshold: i fill -6.5 dB, but display -7dB
I fill -20.4dB, it display -20.4dB, so i am not sure the threshold's step is 0.1dB or 1dB.
compressor ratio: change 100 --> 99.73 --> 91.77 --> 89.26, so what is the step ??
btw, our project requirement is 0.1dB threshold step and 0.1 step compressor ration, could this compressor implement?? thanks
Hello,
1) Unfortunately there is no easy way to initialize values in the data flow. The entire schematic starts out with all data values equal to zero.
2) The GUI for the compressor is just a nice way of letting the user easily configure the 33 points in the compressor table. It only runs on the computer - it doesn't actually run in the DSP. The GUI on the computer calculates the 33 table points that are stored in the DSP. The output gain is calculated by linear interpolation using the 33 table points.
I made a full description of the compressor and how it works here: https://ez.analog.com/docs/DOC-2963
Hello cadie,
Your difference equation y(n)=x(n)+y(n-1) appears to be a high-gain integrator (time constant = 1/fs). You'll find an example integrator with start-stop and adjustable initial condition at https://ez.analog.com/thread/16674
Best regards,
Bob
Hi bob,
according to your method, I creat a cell with feedback and mux, it seems ok, but have to test it many times.
thanks!
cadie.
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EZ Admin
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