| 摘要 |
A TV monitor includes an antenna coupler capable of selectively coupling the TV receiver being monitored to an antenna or an r.f. oscillator. The oscillator is selectively operated to impose an r.f. signal onto the antenna input of the receiver between successive horizontal blanking periods on an active video line. One probe, connected to the horizontal retrace circuit of the receiver monitors the receiver for an "on" or "off" condition. A second probe, connected to the kinescope circuits of the receiver, detects the channel to which the receiver is tuned. A third probe, connected to the vertical retrace circuitry, detects the vertical retrace signal to determine when the r.f. signal is to be imposed onto the receiver's antenna input. By successively stepping the r.f. oscillator through successive frequencies within the bandwidth of individual channels, and by monitoring the kinescope probe for that frequency which compares to that generated, channel identification may be determined. A plurality of individual monitors may be utilized with individual receivers within a household and the data may be collected and stored in a household collector for eventual transmission to a central station.
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