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915MHz signal with a 100MHz A/D
I've been using a Radiotronix DP-1205
RF transceiver that operates in the 915MHz unlicensed ISM band. The
power level, operating frequency, FM deviation, etc., are set using
the SPI serial interface. So I decided to see if my MHZ100Q A/D PCB
could see the signal. I bypassed the antialiasing filter and
associated buffer, and then coupled the transceiver signal to the
It Works! The signal is low amplitude (less than
10% of full scale), and there are a lot of spurs 20dB down or so,
but the carrier is clearly visible. The 902 to 928 MHz band is
being undersampled at 100 MHZ so it shows up at 2 to 28 MHz in the
digitized signal (in full compliance with Nyquist's rules).
The A/D is only spec'ed to 550 MHz, so I wouldn't trust the
signal and distortion levels, but it's definitely a usable
More details on the MHZ100Q
project site at Source Forge.
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