Halve freq gen's 800-960MHz?

[Lou Mathews]

I have a Marconi FM signal generator, model TF 2013, that was designed
for cell phone testing. The frequency range produced is 800-960MHz.

Can someone tell me how feasible it would be to halve the above range
to 400-480MHz, perhaps by bypassing one of the mutiplier stages?

I would suppose that replacing the cystal may cause problems in other
parts of the circuit.

I don't have a circuit diagram at this stage, but can get one
depending on the concensus here.

Or perhaps I can find it by poking around with a DFM.

Thanks for any suggestions.

Lou

 

[Andrew Holme]

"Leon Heller" <leon_heller@hotmail.com> wrote in message news:<4222f00c$0$2765$cc9e4d1f@news-text.dial.pipex.com>...

"Lou Mathews" <loumatthews@pronet.com> wrote in message
news:5ec42197tksvarmj6udfctqm09rtkjtopg@4ax.com...
I have a Marconi FM signal generator, model TF 2013, that was designed
for cell phone testing. The frequency range produced is 800-960MHz.

Can someone tell me how feasible it would be to halve the above range
to 400-480MHz, perhaps by bypassing one of the mutiplier stages?

I would suppose that replacing the cystal may cause problems in other
parts of the circuit.

I don't have a circuit diagram at this stage, but can get one
depending on the concensus here.

Or perhaps I can find it by poking around with a DFM.

Thanks for any suggestions.

Most Marconi signal generators (I've got a couple of 2019As) use PLL
synthesisers, with a VCO running at the output frequency. Changing the
frequency range would involve a lot of redesign work, it's probably not
worth it.

The 2019A uses a doubler for 520 - 1040 MHz.