Communications: directive radio wave systems and devices (e.g. – With particular circuit – Complex signal
Patent
1987-09-28
1989-03-14
Tarcza, Thomas H.
Communications: directive radio wave systems and devices (e.g.,
With particular circuit
Complex signal
328155, 328166, 324 83Q, G01S 740, G01R 2504
Patent
active
048128490
ABSTRACT:
A phase comparator has additional circuitry for correcting nonquadrature error during operation of the comparator. The phase comparator has a 90 degree power divider which receives a reference signal input and produces two reference outputs, one shifted 90 degrees out of phase with the other. The phase comparator also has a zero degree power divider which receives a return signal, such as a reflected signal of a radar transmitter unit. The outputs of the power dividers are applied to mixers and filters to result in an I video output whose frequency is the difference between the reference and signal input frequencies, and a Q video output which is identical in frequency but shifted 90 degrees. The correction circuit includes a frequency trap connected to the reference input and tunable about a center frequency of approximately the third harmonic of the fundamental reference frequency. While the phase comparator is operating, the trap is detuned from the center frequency while the phase error is monitored until the phase error nears zero. Band pass filter means which electrically isolate the power divider from external circuitry can improve operation.
REFERENCES:
patent: 3950750 (1976-04-01), Churchill et al.
patent: 4003054 (1977-01-01), Goldstone
patent: 4122448 (1978-10-01), Martin
patent: 4475088 (1984-10-01), Beard
patent: 4484194 (1984-11-01), Arvidsson
patent: 4489392 (1984-12-01), Lewis
Barron Jr. Gilberto
Bradley James E.
General Dynamics Corporation
Tarcza Thomas H.
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