Rca Inc.

Robert J Maturo

John G Henderson

Danny Chin

As a signal seeking tuner tunes through a number of channels to locate the next active (useable) channel, the display screen of a television receiver is blanked when the receiver is tuned between channels or to an inactive (unuseable) channel for which video signal information is substantially absent. Superimposed over the blanked screen background is a moveable tuning indicator bar, the position of which indicates the channel to which the receiver is tuned. The blanking of the screen prevents the tuning indication from being obscured by background noise.

Television receiver with auxiliary on-screen display

A signal-seeking tuning system for a television receiver scans the VHF and UHF signal bands until a present TV channel signal is detected. Tuning voltage is developed by a digital-to-analog converter in response to a binary word stored in an up-down counter. The value of the binary word increases when a scan-up signal is applied and decreases when a scan-down signal is applied. Scanning is stopped by inhibiting changing of the binary word when a valid sequence of AFT signals is detected. Thereafter, the tuning voltage is compensated for drifts by incrementing or decrementing the binary word whenever the AFT signal departs from a predetermined condition. This correction is inhibited, however, when the RF carrier signal is lost so that the desired tuning is not also lost, whereby the selected channel is still tuned when the RF carrier signal reappears.

Signal-seeking tuning system with signal loss protection for a

In television (TV) receivers, the VHF-TV band including channel 2-13 is perceived by most viewers as being a single TV band even though it is in fact partitioned into lower and upper frequency portions, including channels 2-6 and 7-13, respectively, which are separated by a gap. Voltage controlled tuning systems for such TV receivers employ a tuning voltage which varies over substantially the same range of magnitudes from a lower voltage to a higher voltage for each of the frequency portions of the VHF band. Accordingly, conventional channel indicators responsive to the magnitude of the tuning voltage partition the bands to avoid ambiguity in the channel indication. In the present arrangement, a tuning indicator produces an on-screen bar display having a position which is indicative of the selected channel for all VHF channels as if the VHF frequency band was continuous and not partitioned thereby being consistent with the perception of most viewers. Specifically, the tuning indicator includes a divider device for attenuating the tuning voltage when a channel in the lower or upper VHF band is selected, a device for developing an offsetting voltage when the selected channel is in the upper VHF band, and a device for combining the attenuated tuning voltage and the offsetting voltage to develop a control signal which determines the position of the bar on the TV screen.

Tuning display for a television receiver

A signal-seeking tuning system for a television receiver scans the VHF and UHF signal bands until a present TV channel signal is detected. Tuning voltage is developed by a digital-to-analog converter in response to a binary word stored in an up/down counter. The value of the binary word increases when a scan-up signal is applied and decreases when a scan-down signal is applied. Band signals are automatically sequenced to the next higher frequency band when the binary word 'rolls-over' from a maximum to a minimum value, or to the next lower frequency band when the binary word rolls-over from its minimum to its maximum value. Scanning is stopped by inhibiting changing of the binary word when a valid sequence of AFT signals is detected. Thereafter, the tuning voltage is compensated for drifts by incrementing or decrementing the binary word whenever the AFT signal departs from a predetermined condition. This correction is inhibited, however, when the binary word is at its minimum or maximum value so that unwanted bandswitching is avoided.

Signal-seeking tuning system with automatic bandswitching for a

A television (TV) receiver which receives TV signals in a plurality of TV frequency bands includes apparatus for developing an accentuated and uncontaminated on-screen tuning indication. Specifically, a blanking device is responsive to a tuning signal for eliminating the display of a portion of the TV picture for the duration of a pulse signal. The pulse signal is delayed in time relative to a deflection signal by a time related to the tuning signal so that a blanked bar is generated in the TV picture. A tuning indicator device causes a predetermined display unaffected by the TV picture during the blanked portion of the TV picture.

In a sweep type tuning system capable of sweeping through a desired range of carrier frequencies selectively in one of two directions, a carrier detector includes a discriminator for generating a discriminator signal as the frequency range is swept which has a first amplitude portion when the frequency of a tuned carrier is less than a predetermined nominal value and a second amplitude portion when the frequency of the tuned carrier is greater than the predetermined nominal value. A sequence detector determines the sequence of generation of the first and second portions of the discriminator signal to generate a signal indicating the presence of the tuned carrier. The presence indicating signal is generated when the sweeping takes place in a first direction if the first and then the second portions are sequentially generated and when the sweeping takes place in the second direction if the second and then first portion are sequentially generated.

Carrier detector apparatus useful in a multiband sweep type tuning system

A signal seeking tuning system includes provisions for allowing the direct selection of channels. It includes a memory for storing lower and upper boundaries of a tuning control voltage range for each channel which may be selected. When a channel is selected, a microcomputer causes the memory location corresponding to one of the boundaries associated with the selected channel to be addressed and causes a tuning voltage generator to change the magnitude of the tuning control voltage in the direction of the boundary. A comparator determines when the tuning control voltage reaches the boundary. Thereafter, the microcomputer controls a signal seeking operation between the boundaries to tune the RF carrier associated with the selected channel.

Search type tuning system with direct address channel selection apparatus

In a tuning system for generating a tuning voltage for tuning a television receiver, channel identification apparatus includes a memory for storing binary signals representing boundary voltages having magnitudes corresponding to magnitudes of the tuning voltage between tuning voltage ranges for respective adjacent channels within a band. Because the tuning voltage characteristics associated with conventional television receivers include separated portions corresponding to respective frequency bands in which the television channels are located, boundary voltages corresponding to the boundaries of the tuning voltage ranges of the highest and lowest frequency channels in each band are also stored. As the memory locations are addressed, the boundary voltages are compared to the tuning voltages. Control apparatus causes the memory location associated with the next boundary voltage to be addressed and causes channel number apparatus to generate binary signals representing the next channel number when the magnitude of a predetermined one of the boundary voltage associated with an addressed one of the memory locations and the tuning voltage exceeds the magnitude of the other one. Display apparatus displays the channel number represented by the binary signals generated by the channel number apparatus. Because the boundary voltages are utilized, the channel identification apparatus, as disclosed, is particularly well suited for use in a signal seeking system.

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Bricktown, NJ, United States of America

Robert J Maturo