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Coherent CW. A Brief Review of the State-of-the-Art. George Heron, N2APB. Technical Status. Tx & Rx of precisely timed (12wpm) code Software algorithms synchronize Computer controls the Tx in 1 Hz steps. 0.1s. 0.1s. Precise 12wpm timing. BPSK. CCW is dead … replaced by BPSK
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Coherent CW A Brief Review of the State-of-the-Art George Heron, N2APB
Technical Status • Tx & Rx of precisely timed (12wpm) code • Software algorithms synchronize • Computer controls the Tx in 1 Hz steps 0.1s 0.1s Precise 12wpm timing
BPSK • CCW is dead … replaced by BPSK • BPSK uses Tx/Rx of 800 Hz tones • Better noise immunity • Improved probability of Rx
How? • Sigma-Delta ADC board, by VE2IQ Computer serial port Rx audio 8-bit A/D
Where? • Peter Lumb G3IRM & Bill de Carle VE2IQ have daily BPSK sked on 14.081 MHz at 1600z. Settings: MS25, ET1 enabled. • Active group on BPSK and LOWfer reflectors. (Subscribe to BPSK: messge to majordomo@qth.net with “subscribe bpsk” in body.
A Simple CCW Station Rx A/D RS-232 PC XCVR Tx up/down control and Keyed input
An Advanced CCW Station A/D Converter PC Tx up/down control Tx keying Tx I DSP Audio Processor DDS VFO Phase Splitter R2 Rx Audio Out Q
A More Advanced CCW Station A/D Converter PC Tx up/down control Tx keying Tx I DSP Audio Processor DDS VFO Phase Splitter R2 Rx Audio Out Q Key / Paddle