GB1305995A - - Google Patents

Abstract

1305995 Phase detectors CKD PRAHA OBOROVY PODNIK 15 April 1970 [16 April 1969] 17899/70 Heading H3A The difference in phase between a received and reference voltage, as in a selsyn, is indicated by shaping the received signals, as at 210. producing pulse width modulated pulses in accordance with the phase difference, as at 3, determining the sign of the phase difference, as at 4, and producing an output, as at 6, which represents the phase difference in sign and magnitude. The reference and received signals are available in true and complementary form on leads 221, 222 and 223, 224, respectively. Gate 31 provides an output comprising a pulse train width modulated according to the phase shift between the true signals. Gate 32 provides a pulse train width modulated according to the phase shift between the complementary signals and in anti-phase to the output of gate 31. Gate 33 combines the pulse trains to produce a pulse train at twice the frequency of the received and reference signals. The received and reference signals are supplied to the two elements of a bi-stable circuit 400 in circuit 4 the output 442 of which indicates whether the received signal leads or lags, such indication conditioning the output circuit 6 to produce positive or negative output accordingly. The pulse width modulated pulse train from 3 is subjected to inversions at 5, which allows a blocking signal to be applied at 53, and supplies true and complementary versions of the pulse train to the output circuit 6 which gates the width modulated pulses positive or negative according to the sign indication from 4. The received signal may be three phase converted to single phase and its inverse, Fig. 2, not shown.