GB1193102A - Phase Angle Measurement System. - Google Patents

Abstract

1,193,102. Radio navigation. HOFFMAN ELECTRONICS CORP. 14 June, 1967 [14 June, 1966], No. 27539/67. Heading H4D. [Also in Division G4] Apparatus for use, for example, in a TACAN receiver for measuring the phase angles of signal components of the composite bearing signal waveform includes first and second devices 12, 17, 18, 19 and 14, 30, 31, 33 for phase locking on to incoming signals of 15 cycles per second and 135 cycles per second, the first device giving an output signal during the positive going zero crossing of the 15 cycles per second signal on lead 22 to prime a gate 37 to pass a simultaneously occurring positive going zero crossing of the 135 cycles per second signal from the second device to a gate 50. The gate 50 passes this signal if an amplitude detector 44 indicates that the second device is locked on to, the second signal to cause read out of a counter 54, the count commencing at the positive going zero crossing of a reference signal. If the 135 cycles per second signal is lost the gate 50 passes the positive going zero crossing of the 15 cycles per second signal to cause read out of the counter. If however the 15 cycles per second signal is lost a level detector 26 gives an alarm signal on line 27.