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EP0269094A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Control of rf answer pulses in a tv answer back system

Assignee: TV ANSWER INTERNATIONAL Inc
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Filing: 1987-11-25
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Granted: —
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Expires: 2007-11-25
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Abstract

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 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.

Inventors

  • 👤 Fernando Morales-Garza
  • 👤 Oscar Morales-Garza
  • 👤 Jorge E. Ortiz-Salinas

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-30 10:05
CPC Classifications
H; H04; H04N; H04N7/00; H04N7/16; H04N7/173; H04N7/17309; H04H; H04H20/00; H04H20/65; H04H20/71; H04H20/72; H04H60/00; H04H60/29; H04H60/33; H04H60/76; H04H60/81; H04H60/90; H04N2007/17372

Claims Analysis

Total Claims: 9
Claim 1
Independent Claim 64 words
In a television system providing live and recorded television signal transmissions to a receiver station, apparatus for detecting at the receiver station the live and recorded signals, characterized by, detection means at the receiver station for comparing a timing signal transmitted with the live signals with a time signal being produced at the receiving station to indicate the presence of a live signal transmission.
Claim 2
Dependent Claim 64 words
In a television system providing live and recorded television signal transmissions to a receiver station, apparatus for detecting at the receiver station the live and recorded signals, characterized by, detection means at the receiver station for comparing a timing signal transmitted with the live signals with a time signal being produced at the receiving station to indicate the presence of a live signal transmission.
Claim 3
Dependent Claim 36 words
The television system of Claim 1 further characterized by means at a television transmitting station for accurately controlling a time signal and transmitting it simultaneously with live television signals to distinguish them from recorded television signals.
Claim 4
Dependent Claim 46 words
The television system of Claim 1 further characterized by television query signals transmitted with the live signals, including means at the receiver station responsive to the detection means for producing an answer back signal in response to the query signals only for the live signal transmissions.
Claim 5
Dependent Claim 57 words
The television system of Claim 1 further characterized by automatic time adjustment means at the receiver station comprising a battery backed clock circuit providing said time signal, and means comparing the received time signal with the clock circuit time signal, and means to update the time on the clock circuit in response to the received time signal.
Claim 6
Dependent Claim 65 words
The television system of Claim 1 further characterized by a wireless transmission from a transmitter having an oscillator frequency controlled to a predetermined frequency of a pluraltiy of megahertz within a predetermined accuracy, timing signal transmissions synchronized with the oscillator signals, means at the receiver for receiving and processing the synchronized timing signals to derive therefrom the time signal being produced at the receiver station.
Claim 7
Dependent Claim 61 words
The television system of Claim 5 further characterized by means at the receiver for accurately gating the synchronized timing signal transmissions over a predetermined timing period, means for counting the gated timing signals, oscillator means at the receiver station, and means for automatically controlling the frequency of the oscillator means at the receiver station by means of the gated timing signals.
Claim 8
Dependent Claim 72 words
The television system of Claim 6 further characterized by television query signals transmitted with the live signal transmissions, means synchronized with the oscillator means at a plurality of receiver stations for sending answer back signals from the receiver stations on the same transmission frequency, and means for timing the signals at precise different times from the different receiver stations controlled by the frequency of the oscillator means at the respective receiver stations.
Claim 9
Dependent Claim 46 words
The television system of Claim 1 further characterized by answer back means at the receiver station providing answer back signals responsive to transmitted queries on the live signal transmissions, and synchronization means timing the answer back signals from the timing signals transmitted with the live signals.

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