Victor Poor is one of the first amateurs to lay out the criteria which FSK filters need to satisfy. Poor was the chief engineer at Frederick Electronics (a manufacturer of high end RTTY modems among other products) and is the creator of WinLink 2000.
"A Second Look At Limiterless FSK Detection." RTTY Bulletin, January 1964.
This is the first
time the Page Communications DTC
patent appeared in amateur
literature. The DTC circuit removed the remaining
objection to the use of a limiterless demodulator.
Slow typing without the use of diddles causes the
simpler ATC circuit to throw large amounts of errors.
Note: one of the diodes in Figure 2 of this article is reversed. This was pointed out by Frank Gaudé in a February 1964 article in the RTTY bulletin and acknowledged by Victor Poor himself in his "Comments On DTC Circuit" article in May 1964 (see below).
Note: one of the diodes in Figure 2 of this article is reversed. This was pointed out by Frank Gaudé in a February 1964 article in the RTTY bulletin and acknowledged by Victor Poor himself in his "Comments On DTC Circuit" article in May 1964 (see below).
"Filters For RTTY." RTTY Bulletin, May 1964.
This is the most
definitive article on optimal RTTY filters. Victor Poor
explains that a Matched Filter is the optimal RTTY filter
when there is no interference, and the raised cosine
filter is the optimal filter if the narrowest bandwidth
is desired.
"Comments On DTC Circuit." RTTY Bulletin May 1964
Updates on his
January 1964 article with some comments on time constants
of the DTC circuit.