Nov/Dec 2015 QEX has KD2BD's WWVB-based standard and decoder nicely written up.
His decoder has BPSK demodulation capability, BPSK output is available but for the most part it detects the BPSK only to then remove BPSK prior to carrier phase tracking. Starts with a tuned loop antenna colocated with a 40dB preamp, then a bunch of analog circuitry consisting of discrete NPN's, CMOS SPDT switches and op-amps, 0.025Hz low-pass filter, disciplining a 10MHz TCXO. There is some digital logic (HC390's) to divide the 10MHz TCXO down and produce various standard frequencies, as well as a PIC to decode and display the WWVB time code. Baseband WWVB signals are used to modulate a 1kHz audio tone for aural monitoring. Recommended reading!!! Also there is KD2BD's web description of the same receiver as applied to FMT's: http://www.qsl.net/kd2bd/fmt-methodology.html Tim N3QE _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
