Digital phase-locked loop
Number of patents in Portfolio can not be more than 2000
United States of America Patent
Stats
-
Jan 19, 1993
Grant Date -
N/A
app pub date -
Jun 21, 1991
filing date -
Jun 30, 1990
priority date (Note) -
Expired
status (Latency Note)
Importance
Abstract
A digital phase-locked loop has a periodically overflowing digital oscillator (DCO), implemented as a modulo adder, and a processor device. The processor device adjusts the period T of the digital oscillator to a nominal period, determined from periodically occurring synchronizing pulses, by comparing the actual phase of the digital oscillator with a set phase at the control clock rate of the periodic synchronizing pulses. After the digital oscillator has been locked to the nominal period, the processor device compares the phases by using a double-frequency signal sequence of one-half line period derived from the digital oscillator output signal. The DCO output signal is fed to a correction device where an address-phase signal, locked to the DCO output signal, is generated so that when a non-periodic synchronizing pulse occurs, the address-phase signal is shifted by one period of the signal sequence of one-half line period with respect to the digital oscillator output signal.
First Claim
Other Claims data not available
Family
International Classification(s)
Cited Art Landscape
Patent Citation Ranking
- 14 Citation Count
- H04N Class
- 51.87 % this patent is cited more than
- 32 Age