Abstract: A potentiometer assembly particularly suited for supplying tuning voltages for all of the bands of signals capable of receipt by a television receiver or the like, includes three segments of resistive material arranged in a circle on a support member. Each of the segments corresponds to a different band of frequencies to which the television receiver may be tuned. Band selection is effected by comparable conductive segments on the support member.In one embodiment, a single wiper is used to sweep all of the resistive segments to supply the desired tuning voltage output. A cam arrangement is used to adjust the detented position of the wiper relative to the support member to effect fine tuning at each position. Other embodiments utilize individually adjustable wipers for each station or detent position of the tuner, with each wiper being preset to effect the fine tuning at the detented position of the potentiometer assembly.

Abstract: A television tuning system employs a frequency synthesizer system for establishing the tuning of the receiver. A programmable frequency divider, controlled by a reversible counter, is connected between the output of a reference oscillator and a phase comparator to which the output of the local oscillator in the tuner also is applied. The phase comparator output provides a tuning voltage for controlling the tuning of the local oscillator. A logic circuit is coupled to sense predetermined relationships of signals from a picture carrier detector, a sound carrier detector, an AFT signal, and the presence of vertical synchronization signal components for changing the count in the reversible binary counter to adjust the programmable frequency divider to compensate for channel frequency offsets which may occur in excess of the pull-in range of the AFT circuit.

Abstract: An annular core holder form supports in rotatable fashion a toroidal core in connection with a pair of fixed support members to comprise a core holder assembly for winding wire coils on the core through the action of a revolving wire-carrying shuttle of a coil winding machine. The core holder form is intergally wound to the core through the wrapping action of the shuttle and is removable with the core. The pair of support members and the holder form have generally central first openings extending axially therethrough to permit the shuttle to thread the core, support members and holder form in order to wind the wire coils axially about the annular wall of the core. The support members have respective second openings communicating with the first openings and which are aligned with each other to permit the passage of a winding wire strand.

Abstract: An electronic tuner control system particularly adapted for television receivers employs a gated oscillator for sequentially stepping the tuner from one channel selection to the next. The system includes a counter responsive to the gated oscillator for causing the sequential scanning or stepping to take place in either the "up" or "down" direction. Separate tuning potentiometers are associated with each channel and are selected in sequence under control of the counter. Each potentiometer is set to either a first range of settings indicative of a valid tuning voltage for that channel or to a second range indicating that no tuning or channel selection is to be effected for such a second or "non-preferred" setting. All of the tuning potentiometers are coupled to an analog steering circuit comprised of isolating diodes, and only one potentiometer at a time is selected to apply a tuning voltage to the output of the steering circuit under control of the counter.

Abstract: A first panelboard, having a plurality of frequently used primary control elements arranged thereon, and a second panelboard, having a plurality of occasionally used secondary control elements arranged thereon, extend from a base to provide a module which is pivotally carried by the cabinet of an audio-visual receiving apparatus. Detent means interacting between the module and the cabinet selectively retains either panelboard in the display position. In a further embodiment, the module is enclosed within the cabinet and the selected panelboard is displayed through an opening therein.

Abstract: An automatic chrominance gain control circuit for a color television receiver distinguishes between lower frequency chrominance variations (large color objects) and higher frequency chrominance variations (small objects) to minimize gain control for large color objects and to emphasize gain control for highly saturated contrasting colors in small objects across the picture field.

Abstract: A television receiver includes a switched-mode power supply driven by the horizontal oscillator and driver section of the television receiver. An on/off switch for the receiver is connected to the switched-mode power supply to vary its output according to the setting of the on/off switch. This output, when the switch is "on", is used to supply full operating potential to the cathode ray tube filaments and operating potential for some of the portions of the television receiver. When the on/off switch is in its "off" position, it operates to cause the power supply to supply reduced or standby potentials to those same portions of the receiver and to the cathode ray tube filaments. At the same time, other portions of the receiver are turned off and on in the normal fashion.

Abstract: An adjustment tool for a rotatable preset potentiometer used in television receivers, or the like, is formed of one-piece, molded plastic material and is insertable into the hollow rotatable hub of the potentiometer. The tool has a shaft which extends into and through the hub of the potentiometer. A resilient, deformable locking member which normally expands to a size greater than the hole in the hub, is carried on one end of the shaft. The locking member is compressible upon insertion into and removal from the hub, and is located to expand outside the hub when the tool is inserted into place. Drive slots are formed in the end of the hub. The tool has a pair of drive slot engaging members at its other end which limit the depth to which the tool can be inserted. These members engage the slots in the hub to permit the tool and the hub to be rotated together. An enlarged head is formed on the end of the shaft having the slot engaging members on it and is of a size to permit it to be grasped for manual rotation.

Abstract: A wide-band automatic fine tuning (AFT) circuit capable of a .+-.2 MHz pull-in range without false lockups responds to the output of a picture carrier discriminator, a sound carrier discriminator and a vertical synchronizing signal sensing means to operate a reversible digital counter in either its count up or count down direction depending upon the relationship of the outputs of the two discriminators and the synchronizing signal sensing circuit. The output of the counter is supplied to a digital-to-analog converter which produces a tuning control voltage used for controlling the frequency of operation of the local oscillator of the receiver. The output of the digital-to-analog converter is added to a conventional AFT voltage which maintains the desired tuning once it has been established by the wide-band AFT system.

Abstract: A multiband tuner control system, particularly adapted for television receivers, utilizes, a three-band varactor VHF tuner. The bands include low and high band VHF signals and a third band of signals obtained from the UHF signals following a first conversion to a third VHF frequency band. This third band is selectively switched to the tuner under the control of channel selection switches. The channel selection switches also cause the conversion of UHF signals to the VHF band to be effected by mixing the UHF signals with a different fixed frequency local oscillator signal in the first converter for each different decade of channels of the UHF signal. The channel selection switches automatically cause this to happen and also select a proper tuning potentiometer associated with the selected UHF or VHF band directly in accordance with the two-digit channel number.

Abstract: An automatic fine tuning defeat circuit disables the application of an automatic fine tuning or automatic frequency control correction voltage to the voltage-controlled tuners of a television receiver during switching from one channel to another. The tuning voltage for a selected channel is coupled in series with the automatic frequency control voltage to provide a composite tuning voltage for the tuners. During a channel change, a switch is rendered conductive to shunt or short-circuit the output of the automatic frequency control circuit, thereby rendering its output ineffective for control of the tuners during channel change. Upon completion of the channel change, the automatic frequency control circuit output voltage again is applied in series with the tuning voltage to form the composite tuning voltage for the tuners.