Analog and digital phase detector for bit synchronism

Claim 1

An analog digital phase detector for bit synchronism comprising: means for providing noninverting phase clock pulses and inverting phase clock pulses from clock pulses of a VCO(Voltage-Controlled Oscillator) or phase-controlled circuit; retiming means adapted to retime the received NRZ data with the noninverting phase clock pulses and the inverting phase clock pulses from the noninverting phase and inverting phase clock pulses providing means; phase discrepancy extracting means for extracting the phase discrepancy between the NRZ data retimed with the noninverting phase clock pulses from said noninverting phase and inverting phase clock pulses providing means and the received NRZ data and providing said phase discrepancy in noninverting phase and inverting phase fashion; reference phase extracting means for extracting the phase discrepancy between the NRZ data retimed with the noninverting phase clock pulses from the noninverting phase and inverting phase clock pulses providing means and the data retimed with the inverting phase clock pulses and providing reference phase in noninverting phase and inverting phase fashion; leading phase pulse providing means connected to the output of said phase discrepancy extracting means and the output of said reference phase extracting means and adapted to provide a digital output which is indicative of the phase discrepancy produced when the phase of the center of the data bit interval is retarded relative to the phase of the transition of the clock pulses; and trailing phase pulse providing means connected to the output of said phase discrepancy extracting means and the output of said reference phase extracting means and adapted to provide a digital output which is indicative of the phase discrepancy produced when the phase of the center of the data bit interval is advanced relative to the phase of the transition of the clock pulses, so that the phase detection can be carried out not only in analog fashion by the comparison between the output from the phase discrepancy extracting means and the output from the reference phase extracting means, but also in digital fashion by means of said leading phase pulse providing means and said trailing phase pulse proving means, wherein said retiming means comprises a first D-type flip-flop having a clock pulse input receiving the noninverted phase clock pulses from said noninverted phase and inverted phase clock pulses providing means and a data input receiving the NRZ data and a second D-type flip-flop having a clock pulse input receiving the inverted phase clock pulses from said noninverted phase and inverted phase clock pulses providing means and a data input receiving the NRZ data, wherein said phase discrepancy extracting means comprises an exclusive OR- and NOR-gate receiving the output from said first D-type flip-flop and the NRZ data, wherein aid reference phase extracting means comprises an exclusive OR- and NOR-gate receiving the output from said first D-type flip-flop and the output of said second D-type flip-flop, wherein said leading phase pulse providing means comprises a NOR-gate receiving the exclusive OR-output from said exclusive OR- and NOR-gate of the phase discrepancy extracting means and the exclusive NOR-output from said exclusive OR- and NOR-gate of the reference phase extracting means, and wherein said trailing phase pulse providing means comprises a NOR-gate receiving the exclusive NOR-output from said exclusive OR- and NOR-gate of the phase discrepancy extracting means and the exclusive NOR-output from said exclusive OR- and NOR-gate of the reference phase extracting means.