Abstract: A tuning system for a television receiver includes a channel number generator coupled to nominal tuning memories, fine tune memories and slope factor memories. The memory outputs are coupled to a corresponding plurality of comparators which are also coupled to counters for deriving pulse-width modulated (PWM) signals corresponding to tuning information stored in the memories. The PWM signals are supplied to a tuning voltage generator where they are combined to produce the tuning voltage for the tuner. The information in the slope factor memories is based upon the slope of the tuning curve corresponding to the selected channel number. The final tuning voltage consists of the nominal tuning voltage combined with the product of the fine tune voltage and slope factor.

Abstract: In a transmitter designed for periods of extended use, means for sensing the ambient temperature in which the transmitter would operate if activated and adjusting the initial output power of the transmitter so as to reduce the initial output power of the transmitter to maximize or increase the power output above that obtainable using existing protective techniques over an extended period.

Abstract: This is a self-contained control unit for use in an automobile or other vehicle which has a citizens band radio receiver and an additional audio entertainment appliance, such as an AM radio, FM radio, AM/FM radio, or an audio magnetic tape player. The control unit includes an external speaker for the CB receiver, a plug for insertion in a jack on the CB receiver to connect the external speaker to it, a relay for controlling the operation of the additional audio entertainment appliance, and a transistor amplifier and switching circuit connected between the plug and the relay to disable the additional audio entertainment appliance whenever the CB receiver is broadcasting incoming CB signals through the external speaker. The switching circuit includes a time delay arrangement which delays turning on the additional audio entertainment appliance after the incoming CB signal has stopped.