[Lf] RF gain IC

[Andre' Kesteloot]

Rik Strobbe wrote:

> At 14:24 19/07/00 +0100, G4JNT wrote:
> >For some time I have been searching for a decent modern IC for the gain
> >controlled IF amplification function in a linear (SSB etc.) receiver but
> >have had no luck finding what I'm looking for.
>
> Hi Andy,
>
> I've used a 8-bit DAC (digital analog convertor) as 'digital controlled
> amplifier'.
> Basicaly you replace the DAC reference voltage by the AC input signal and
> get the amplified (or attenuated) signal at the DAC output. Gain is
> controlled by the digital input of the DAC. Dynamic range depends on the
> number of bits (of the digital input), a 8-bit DAC gives about 48dB, a
> 12-bit 72dB and a 16-bit DAC even a respectable 96dB (if you manage to get
> the proper PCB layout).
>
> As I only needed 40dB dynamic range I used a cheap DAC-08 from Analog Devices.
> It worked fine at 240kHz, I belive that the application note gave a 1MHz
> limit.
> But more recent (faster) DAC's might be good for higher frequencies.
>
> I believe I have the application note still somewhere (as PDF file), if you
> want I can search it and mail it to you.
>
> 73, Rik  ON7YD