Audio Compressor with TDA4050B
Audio Compressor with TDA4050B
(OP)
I think of evaluating a preamplifier with an automatic level control for audio frequecies (aka: audio compressor)in the range of 300-3000Hz to give a DSP a relatively constant input level.
I came across the TDA4050B which is obsolete but still very cheap available. This IC has a dynamic range of some 80dB! The application in the original datasheet has a passive RC-filter, this preamp was designed for usage with IR reomte controls as a preamp for the IR receiver.
How do I need to redesign the RC-filter for the range of audio frequencies I want to use? The original datasheet does not mention the purpose of this RC-filter in any way
I came across the TDA4050B which is obsolete but still very cheap available. This IC has a dynamic range of some 80dB! The application in the original datasheet has a passive RC-filter, this preamp was designed for usage with IR reomte controls as a preamp for the IR receiver.
How do I need to redesign the RC-filter for the range of audio frequencies I want to use? The original datasheet does not mention the purpose of this RC-filter in any way





RE: Audio Compressor with TDA4050B
Benta.
RE: Audio Compressor with TDA4050B
While you can avoid input distortion by lowering the level of your signal under, say, 20mVpp and adjust the pass band by changing the R&C values of the filter, there is no way to change the shape of the output signal...
So, just forget about this IC and look for analog/specialized IC's like the one suggested by benta.
RE: Audio Compressor with TDA4050B
I'm assuming your application is hinted by your handle (hfnobile) and the required comm 300-3k bandpass.
Another option (gold plating?) would be to use the DSP to provide a gain control output signal back into an analog AGC stage. The trick is often providing the voltage controlled gain stage, but there are many tricks to implement that. Old tricks include using light bulbs and CDS photocells. New approach would be a gain stage with a digital gain control input.
RE: Audio Compressor with TDA4050B
VE1BLL, I have no access to the DSP circuit nor its software, and you are right: as I am an "hf-man", audio is from 0.3-3.0, hi.
Back to the '4050: The giant dynamic range of 80dB and the fast-attack/slow-release circuit are interesting. I will give it a try with some audio signal, recalculating the filter for 1.5kHz or so.
Another idea would be to "go back" to Plessey's VOGAD and AGC circuits, as I know they work VERY well and as I just need ONE working circuit, the financial risk is small.
RE: Audio Compressor with TDA4050B
http://dk3hn.homepage.t-online.de/elek_fram.htm
Thanks to all!
Andy
RE: Audio Compressor with TDA4050B
Gunnar Englund
www.gke.org
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100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Audio Compressor with TDA4050B
yes, you are right. Certain old analog circuits ARE excellent and one is keeping the balls flying low
Andy