FM/AM Tuner

[davidsrsb]

Pulse counting was by Sony.
I suspect it's a monostable or PLL version.
I have a ST-S361 which was a pretty good product.

Getting parts to make a tuner is hard these days, the old CA3089/MC1310s are long gone.

The dominant player is ROHM and most of their data sheets are not in English.

[davidsrsb]

Some modern designs do the stereo decoder in DSP, certainly a lot more stable than the original analogue method.

A commercial tuner could be upgraded by many of the same methods as a CD player and probably with a lot more effect. The RF section of a tuner is very sensitive to vibration so case and pcb damping is important. Supply decoupling and PLL loop filtering is going to be compromised by costs and the single sided pcb common to these products.

I haven't bothered because the radio stations here are ****
We don't have DAB yet, although most stations are available via the satellite tv decoder with MP3 compression.

[arensattic]

Hallo folks,

A guy from down under has built a pulse counting FM receiver with vacuum tubes. He explains the principle of operation and he says that his (relatively simple) design works very well. See his website at http://www.users.bigpond.com/cool386
The site has plans for many other FM receivers with varying complexity.

Have myself built two FM receivers lately (not from the Aussie site) and may report about them soon.

Best regards,

Aren (from arensattic)

http://home.hetnet.nl/~a.van.waarde/index.html

[forr]

Thanks, Arensattic, for the links.
I think Cyril Bateman told that, among his first home-made PCB's, there was a pulse counting FM tuner whose solid state circuit was published in Wireless World before 1970. I remember having seen an other pulse counting receiver, very simple, in a french magazine around 1966. I would be curious to see these schametics.

Regards ~~~~ Forr

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[arensattic]

Hallo Forr,

Unfortunately I don't have the Bateman solid-state schematic, and I also do not have access to very old issues of Wireless World since they are not in our local university library. If you had an exact reference I could get photocopies for you through our national library network (e.g. from the Technical Universities at Eindhoven or at Delft). It seems that mr Bateman is still alive so we could try to contact him by e-mail. (I would definitely also be interested in seeing this solid-state circuit from the 1960s !).

The only pulse counting schematic which I have (besides that of John Hunter, webmaster of the Australian site) is for a valve FM tuner. It was published by the Belgian author G.Govaert in the 1972 volume of the Dutch magazine Radio Elektronica.

There were many FM tuner schematics published in the magazine Elektuur (Elektor) during the 1970s and 1980s, and I have collected these. Most of them were based on the phase locked loop principle.

Hopefully either mr Bateman or one of our fellow forum members can satisfy our curiosity.

Best regards,

Aren

[forr]

Hi Arensattic,

Having built some of Cyril Bateman's projects, I've been in correspondance with him. I asked him if he could provide some precisions about his home-made pulse counting FM receiver. He could just tell a bit about the techniques but, sadly, did not have anymore the schematics.

regards ~~~~~ Forr

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[Nordic]

These are all mono?

[davidsrsb]

Pulse counters are basically monostables, with a period of about 50% of the carrier, triggered by one of the edges of the carrier. As the frequency varies the output duty cycle will also vary.

To get a usable circuit the IF must be low so that the fm deviation (+/-75KHz) actually produces a significant output. 10.7 MHz is far too high.

[gpapag]

kENWOOD has utilised this topology in some of it's tuners. Have a look here:
http://www.fmtunerinfo.com/kenwood.html
Regards
George

[forr]

Hi Gpapag,

I was sure that Kenwood had used pulse counting techniques. You confirm, thanks. However, your link is not valid, here's the right one :

http://www.fmtunerinfo.com/kenwood.html