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Re: Adding speech compression.

 

Right Farhan
Your idea is good and cheap to try.
RF clippers are the best.
Simple AF processing is second best as the artifacts are inside the audio passband..
If I remember correctly, there was an RF clipper in the old ARRL SSB Handbook that clipped the DSB before the filter to use the filter for filtering the sideband and resulting artifacts.
I will try to find it and post the article to get the idea but it used a valve not a transistor.


On Mon, Apr 3, 2017 at 9:14 PM, Ashhar Farhan <farhanbox@...> wrote:
the easy way is to just speak close to the mic and allow the mic amp to do all the audio clipping. audio clipping introduces artifacts inside the audio passband (harmonics of a clipped 500 Hz are at 1000Hz, 1500 Hz, 2500Hz, etc.)
the better way is to clip the RF. That way, the harmonics of 12 Mhz are at 24, 36 etc that are filtered away. So, the easy way to do that is to put two back to back germanium diodes at the crystal filter towards the BFO side.?
- f

On Mon, Apr 3, 2017 at 11:53 PM, John Smith via Groups.Io <johnlinux77=yahoo.com@groups.io> wrote:

I am still wanting to find out if anyone has done something like this with the BITX40. I am still not sure if this pig is worth that much lipstick. Did microphone gain help folks with low audio input. Is seems people have plans, but don't do or talk about them for some reason. I haven't even connected the audio jacks because there is nothing to do with it at this point. Digital modes are what most people are wanting. Someone should think about a BITX for digital modes only.? I'd buy one, if it's cheap. But yea, I have read a lot about this as a solution for folks who think it doesn't have enough grunt. Me too. But I have been happy with getting more power out as is. But with an average output around 10-12W while 25W steady from a tone generator is possible. I would really like to increase my average output a bit. Within reason.?

I look forward to reading your results as I begin sourcing parts to help decide on a circuit to start with. Someone emailed this one to me. It seems easy to make, but I don't know what type of speech processor it is. I'll probably start here.
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