I guess Yaesu was one of the pioneers of RF speech processing way back in the early 70's with the Ft-101 series of transceivers. The way that these RF Processors work is they convert the audio from the mic input to RF with a SSB generator. They use clipping at the RF level and filter the harmonics there which is very easy. Then they convert this SSB signal back to audio with a detector. All the older vintage analog transceivers used this method (Kenwood TS940, 850, Yaesu Ft-990, etc.) Obviously this can be done in DSP because all the new rigs do so with good results (Orion, FT-1000 series, Kenwood TS-870, Icom ProIII) ----- Original Message ----- From: "Jim Lux" <[EMAIL PROTECTED]> To: "Frank Mayer" <[EMAIL PROTECTED]>; "Greg - ZL3IX" <[EMAIL PROTECTED]>; <flexradio@flex-radio.biz> Sent: Thursday, May 31, 2007 9:12 AM Subject: Re: [Flexradio] Audio Punch
> At 01:33 AM 5/31/2007, Frank Mayer wrote: > >I am in agreement with you Greg as far as the clipper goes. Some of the > >other posts so far are saying to use external gear. That's ok for the > >"audio" boys but an RF Clipper is a different animal. I don't believe > >anyone is manufacturing an external unit anymore. I do believe that a good > >RF Clipper/Processor is an essential feature that must be included IN a rig. > >Just like RIT, etc. I wonder if this type of circuit CAN be written in > >software. > > > Yes, it can. Assuming that you want to generate a signal with a > bandwidth less than, say, 20 kHz, the SDR1000 can generate it. All > it takes is the software, and to do that,you have to have a good > mathematical description of what you want. > > The problem (I suspect) is that describing exactly what it is you > want is a bit tricky. Obviously, it's not just an audio clipper (or > you'd have already done that), so what you really are depending on is > some sort of filtered non-linearity somewhere in the if/rf chain, and > that doesn't necessarily have a convenient description. In > particular, it's probably very radio mfr/model dependent. (sort of > like musicians preferring a particular type of distortion and sound > in their guitar amp) > > Jim, W6RMK > > > > > > > -- > No virus found in this incoming message. > Checked by AVG Free Edition. > Version: 7.5.472 / Virus Database: 269.8.0/821 - Release Date: 5/27/2007 3:05 PM > > _______________________________________________ FlexRadio mailing list FlexRadio@flex-radio.biz http://mail.flex-radio.biz/mailman/listinfo/flexradio_flex-radio.biz Archive Link: http://www.mail-archive.com/flexradio%40flex-radio.biz/ FlexRadio Knowledge Base: http://kb.flex-radio.com/ FlexRadio Homepage: http://www.flex-radio.com/
