Method and circuit for recovering a sync signal fed via a cable to a raster scan display device
OwnerJoseph Kramerinventor
Life of this patent
Estimating the term…
Abstract
In a method and circuit for recovering a sync signal from an input sync signal passing through a cable to a display device, an average value of the input sync signal is obtained during a predetermined time period so as to obtain a sync threshold, which is compared with the input sync signal. A sync signal is output when the input sync signal is greater than the sync threshold.
Claims8
A method for recovering a sync signal from an input sync signal passing through a cable to a display device, the method comprising:
- obtaining a weighted reference value of the input sync signal during a predetermined time period so as to obtain a sync threshold that is automatically adapted to a polarity of the input sync signal;
- comparing the input sync signal with the sync threshold;
- and outputting a sync signal when the input sync signal is greater than the sync threshold for a positive going sync signal and when the input sync signal is less than the sync threshold for a negative going sync signal.
A circuit for recovering a sync signal from an input sync signal passing through a cable to display device, the circuit comprising:
- a weighted integrator for obtaining a sync threshold that is automatically adapted to a polarity of the input sync signal, and
- a comparator for comparing the input sync signal with said sync threshold and outputting a sync signal when the input sync signal is greater than the sync threshold.
The circuit according to claim, comprising:
- an input coupled to ground via a voltage divider comprising a pair of resistors having a common junction fed to a first input of the comparator, said weighted integrator including
- a rectifier coupled via a resistor for feeding a rectified portion of the input sync signal to a peak detector having an output fed to a second input of the comparator, and
- at least one output coupled to an output of the comparator for feeding a recovered TTL sync signal to a respective display monitor.
Dependencies are inferred from the claim text.