Control of rf answer pulses in a TV answer back system

Details Control of rf answer pulses in a TV answer back system Control of rf answer pulses in a TV answer back system

1986-11-25

1988-07-05

George, Keith E.

Facsimile and static presentation processing

Static presentation processing

Attribute control

331 1A, 455 75, H04H 900

Patent

active

047558717

ABSTRACT:
In a TV answer back system where many receiver stations communicate with a TV transmitter station by means of rf pulses generated by rf oscillators at the receiver station, the requirement for keeping all oscillators on frequency is achieved without crystal temperature control by automatically controlling the rf oscillator frequency using synchronization signals carried in the video signal received from the TV studio. By this invention it has been possible to control the frequency of multiple megahertz oscillator as accurately as desired from relatively low frequency synchronizing signals such as the vertical and horizontal video sync pulses. Thus an oscillations counter is gated for a very accurate time period by the sync pulses, and the oscillation count is compared with a datum count representing the desired oscillation frequency. The requirement to prevent receiver stations from answering with rf pulses in response to queries contained in home video recordings of previously broadcast signals is achieved by encoding broadcast time on all query containing TV transmissions, and by comparing at receiver stations broadcast time information from received signal with time from a local battery backed clock contained at each receiver station, thus discrimination of video recordings is possible by comparing received video broadcast time with local time.

REFERENCES:
patent: 3997718 (1976-12-01), Ricketts et al.
patent: 4025851 (1977-03-01), Haselwood et al.
patent: 4450518 (1984-05-01), Klee
patent: 4494111 (1985-01-01), Rocci et al.
patent: 4520508 (1985-05-01), Reichert, Jr.
patent: 4591906 (1986-05-01), Morales-Garza et al.
patent: 4630108 (1986-12-01), Gomersall

Affiliated with

Also associated with

Rating

Control of rf answer pulses in a TV answer back system does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Control of rf answer pulses in a TV answer back system, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Control of rf answer pulses in a TV answer back system will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-2335793