Method for assisting simple synchronization to the carrier of a dispersed-energy QPSK signal

An apparatus for synchronization of a received carrier to a transmitted carrier of dispersed-energy quadrature phase shift keying (QPSK) signals, comprising:

• a QPSK demodulator, including:
• an oscillator circuit generating a TI carrier signal and a TQ carrier signal phrase-shifted through 90° with respect to the TI carrier signal;
• a first mixing stage receiving and mixing the TI carrier signal and a received QPSK signal resulting in an SI signal;
• a second mixing stage receiving and mixing the TQ carrier signal and the received QPSK signal resulting in an SQ signal;
• and
• a synchronization device having a trigger circuit receiving the SI signal and generating an output signal, a sample and hold circuit receiving the SQ signal and the output signal from said trigger circuit and generating an output signal, and an averaging circuit receiving the output signal from said sample and hold circuit and generating an actuating signal received by said oscillator circuit, said actuating signal being a measure of a discrepancy from synchronicity between the received carrier and the transmitted carrier.

An apparatus for synchronization of a received carrier to a transmitted carrier of dispersed-energy quadrature phase shift keying (QPSK) signals, comprising:

• a QPSK demodulator, including:
• an oscillator circuit generating a TI carrier signal and a TQ carrier signal phase-shifted through 90° with respect to the TI carrier signal;
• a first mixing stage receiving and mixing the TI carrier signal and a received QPSK signal resulting in an SI signal;
• a second mixing stage receiving and mixing the TQ carrier signal and the received QPSK signal resulting in an SQ signal;
• and
• a synchronization device having a trigger circuit receiving the SQ signal and generating an output signal, a sample and hold circuit receiving the SI signal and the output signal from said trigger circuit and generating an output signal, and an averaging circuit receiving the output signal from said sample and hold circuit and generating an actuating signal received by said oscillator circuit, said actuating signal being a measure of a discrepancy from synchronicity between the received carrier and the transmitted carrier.