Electronic – UHF Phase Modulation

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I would like to design a system that produces -10 degrees and +10 degrees phase shifts at 409.6MHz (Basically BPSK).

The way I'm thinking about approaching this is by using a DDS to generate the BPSK at 12.8MHz and up-converting using a mixer to 409.6MHz, filtering, and amplifying to +10dBm.

Is this the best way to do this? I have also read that I can use a 32x PLL multiplier… would that be a better way?

Factors I am taking into consideration:

  1. Complexity to design circuit/pcb

  2. Cost of components

  3. Low phase noise, low spurs, emi, etc.

  4. Using a 12.8MHz ovenized oscillator (as 12.8 x 32 = 409.6)

Best Answer

The best way to go about doing this is basically bypassing the DDS altogether and generating the baseband from a DSP and generating the symbols using a IQ Modulator. A VCO based PLL can be used to generate an LO for the modulator.

Additionally, the magnitude of the I & Q baseband voltages has the following relation:

Vq = -tan(10°) * Vi
Vq = -tan(-10°) * Vi

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