Hello Peter: Why do you not tell us a little about the test of the new IC
756PRO in the recent issue of your RADIO COMMUNICATIONS? And someone in
Germany: what did CQ-DL say about dynamic range?
73s de Hans SM5KI
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>Från: Peter Chadwick <Peter_Chadwick@mitel.com>
>Till: Michael Tope <W4EF@pacbell.net>, "'W8JI@contesting.com'"
<W8JI@contesting.com>
>Kopia: amps@contesting.com
>Ämne: RE: [AMPS] Receiver performance
>Datum: tor 16 mar 2000 16.25
>
>
>Tom says;
>
>>The problem is dynamic range, and the fact the DSP is way down
>>the chain from the mixers.
>
>Maybe we have to define exactly what is meant by dynamic range here.
>
>It would appear from the DSP gurus that by oversampling, we should be able
>to get the 'dynamic range'. My boss just brought me some text to look at on
>the subject. Because oversampling appears to work by effectively averaging
>the values of the samples, I can see it working on noise. I am not sure that
>I can see how it does it on IMD and non linearities of that sort.
>
>So I think I still like the idea of a first IF between 1.4 and 10MHz, and a
>first filter (or filters) that are about 2.7kHz wide for SSB and selectable
>between 250 and 850Hz for CW.
>
>Then another set of filters to allow shift/width, and then DSP at audio.
>
>A project for retirement - I have a set of 455 filters, USB, LSB, AM, all
>Collins mechanical, and 500 and 250Hz crystal, as well as a lot of 1.4MHz
>USB/LSB/AM and CW filters.
>
>But with DSP on transmit, we could, at least in theory, pre-distort the SSB
>signal such that even a Class C PA would give out a clean signal on SSB.
>We could certainly clean up the G2DAF amp!!!
>
>73
>
>Peter G3RZP
>
>
>
>
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