Auto tune modulator

A bit of speculation backed up by experiment.

To use my MW/LW (AM) radios with modern sources (DAB etc.) I have got a modulator, this works a treat but hasn't got that 'tune into another station' feel to it. To this end I have been experimenting with determining the local oscillator frequency and then switching sources and the transmitted frequency. The outcome would be when you tune the radio the modulator switches to another station (pressing a button on a DAB radio for example) and then outputs that to another frequency, it is just like really tuning in a radio (I hope).

I have managed to determine the LO frequency using a DSP chip (the hard bit) and can see no problem using a digital frequency synthesizer to generate the station signal. To stop off air signals interfering this would probably have to be 'closed circuit'.

The reason for telling you all this is that if there is interest in such a thing I will do a 'proper job' and make a small run of them, if not it's going to be a one off bodge.

I would like some ideas as how to interface to the source, I was thinking of having a few relays or an infra red output (with a 'learn' facility) to control it.

If it turns out to be popular I would guess £50 to £100 for a unit.

Comments and interest please...

MM

[Refugee]

I have just given a little thought.
Would it be worth adding a level indicator on the LO and also a second sensor also with level indication for the IF?
It could then also be used as a quick tool for setting up "got at" sets as an added bonus.

As I want to have the thing 'set up able' via USB those enhancements are only software, so yes. It could also a wobbulator, I intend (if it has any popularity) to do the software as open source, anything is possible then!