[time-nuts] VLF Phase-tracking receivers.

Martin VE3OAT ve3oat at storm.ca
Sun Aug 10 15:24:16 EDT 2014

As I recall (it was a long time ago), it was called Minimum Shift 
Keying and used the minimum frequency shift (FSK) that would permit 
reliable detection of a bit (mark or space) at the given information 
rate.  Something like 25 Hz shift at 50 baud keying.  But it was 
necessary to control the instantaneous phase of the signal very 
carefully.  As a result the spectrum of an MSK signal is quite 
distinct from that of an ordinary FSK signal.  As I recall.

... Martin    VE3OAT

Ken W7EKB wrote :
> As I understand it from back in the 1970s when I was first working on this
> sort of thing, the modulation is not FSK, but "MSK" (whatever that is) at
> something like 25 to 50 Hz, ... (snip)

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