Elektronische Schaltung zur Messung der Phasen- und Frequenzdifferenz zweier periodischer Signale

An electronic circuit is proposed for the measurement of the phase and frequency difference of two periodic signals which are applied to the inputs (7, 8) of a comparator (1). The comparator comprises a state machine (2) preferably implemented by a ring counter, a shift register (3), two state detection logic circuits (4, 5) and a comparison logic circuit (6) whose output forms the output (9) of the comparator. The state machine (2) works cyclically and serially with at least two states. A first periodic signal is connected to its clock input. An output, to which the inner states of the machine are output as periodic pulse trains, is connected to the shift register (3). A further output is connected to the state detection logic (4). The second periodic signal, whose phase shift compared with the first periodic signal is to be measured, is connected to the shift register (3) via the input (8). In the event of phase coincidence of the two periodic input signals, the internal states of th e state machine (2) and the shift register (3) change in common mode. Accordingly, a constant signal is output at the output (9). If a phase shift occurs, the shift register (3) continues to be clocked offset in time by the phase difference and, accordingly, a phase difference signal is output at the output (9). The state changes only take place due to ...