Phase detection system

Abstract

A phase detection system in which a triangular reference signal which is substantially similar in waveform, frequency and amplitude to an input signal is used and at a time of detection whether the reference and input signal are rising or falling is detected and also whether or not the input signal is greater than an auxiliary or complementary signal derived by subtracting the reference signal from a constant DC signal whose amplitude is equal to a maximum amplitude of the reference signal is detected. Operations are executed based upon the detection results so that an output signal representative of an instantaneous phase difference between the input and reference signals is obtained without any delay in time. The relationships between operands and results in operations are as follows: (a) when both the reference and input signals are rising simultaneously, the result represents the input signal minus the reference signal; (b) when the reference and input signals are falling simultaneously, the result represents the reference signal minus the input signal; (c) when the reference signal is rising while the input signal is falling and (i) if the input signal is greater than the auxiliary or complementary signal, the result represents a shifted signal minus the auxiliary or complementary signal, the shifted signal being obtained by negatively shifting in amplitude the input signal by an amount equal to its amplitude, but (ii) if the input signal is smaller than the complementary signal, the result represents the input signal minus the complementary signal; and (d) when the reference signal is falling while the input signal is rising and (i) if the input signal is greater than the complementary signal, the result represents the complementary signal minus the shifted signal, but (ii) if the input signal is smaller than the complementary signal, the result represents the sum of the input and reference signals.

Dependencies are inferred from the claim text.