Re: LW/AM/SW radio very cheap in laptop?



— On Thu, 4/2/09, John G. removed_email_address@domain.invalid wrote:

There’s another chance to get kids into radio…

If a high volume kids’ laptop had stereo “HD audio” ports available
(24-bit 192 kHz converters, 95 db input and 100 db output), how cheap
and small a circuit could you build onto that motherboard to provide
useful LW/AM radio reception?


Here is my 2 cents:

  1. AM signals known to be strong, RF Gain may not be required.

  2. Undersampling can be used to downconvert/digitize AM signals.

  3. RF Tunning is the problem. We have to think for away to use the
    voltage from one of the audio output ports to control a bandpass filter
    center frequency (voltage controlled filter).

  4. Software demodulation.

Best Regards,