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How can I realize an UP converter from 300 MHZ to UHF band

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borgomauro

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I can obtain by a DAC a DVB-T signal up to 350 MHz.
Which is the best up-conversion scheme to the entire UHF band (474 - 860 MHz) in order to use as few as possible Output filter (to overcome spurs & clock).

Can you suggest me some circuit elements such as VCO/PLL and mixer ?

Thank you all for your answers,
Mauro
 

Re: How can I realize an UP converter from 300 MHZ to UHF ba

For upconversion of the 350MHz signal to 474MHz - 860 MHz you can use a mixer and a PLL using a VCO from 824MHz - 1210MHz.

**broken link removed**
http://www.crystek.com/microwave/index.php
 

Re: How can I realize an UP converter from 300 MHZ to UHF ba

Thank you for suggestion.
My main problem is to clear all the spurs after the mixer. So My idea was to double convert the signal in order to obtain less than possible spurs.
 

Re: How can I realize an UP converter from 300 MHZ to UHF ba

You can not double (using a frequency multiplier) the DVB-T signal because uses QPSK, 16QAM or 64QAM modulations, which are not constant envelope.
Only signals using constant envelope modulations as FM, GMSK, GFSK, etc. could be doubled, without distorting the data.
 

I/Q modulation would be the usual way to perform precise upconversion with this kind of signals.
 

Re: How can I realize an UP converter from 300 MHZ to UHF ba

If I were going for performance over cost, I would probably upconvert it to a fixed IF frequency, maybe 1200 mhz, filter it well, and then downconvert it to the desired frequency with a high side LO--lowpass filtering out the 2nd LO and many of the intermod products. I would use a high LO power/very linear mixer, for both frequency conversions.

Rich
 
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Re: How can I realize an UP converter from 300 MHZ to UHF ba

Thank Biff, that was my idea (I've bad exaplined).
There are a lot of surface mount mixers out there, can you suggest me some of them?

Is there exists an integrated mixer and VCO, or mixer and PLL ?
 

Re: How can I realize an UP converter from 300 MHZ to UHF ba

Well, not off the top of my head. You can look thru the standard suspects, like maxim, analog devices, nec, triquint, hittite, atmel, rfmd, etc. Maybe go to digikey and search thru their rf products for a hint.
 

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