Portable radio frequency/channel display system

In a portable radio device of the type which is powered by a battery or other depletable power source, and which includes a plurality of controls for operating a corresponding plurality of radio functions and a display for indicating the frequency or channel to which the radio is tuned, a display control system comprising:

• sensing means coupled to said controls for generating an initiation signal in response to the operation of any of said functions by said controls;
• detecting means coupled to said sensing means and responsive to said initiation signal for developing a control signal in response to the generation of said initiation signal;
• signal lengthening means coupled to said detector means and responsive to said control signal for effectively lengthening the duration of said control signal for a predetermined amount of time;
• and switch means coupled between said display and said battery and responsive to said lengthened control signal for causing said display to be energized by said battery for said predetermined amount of time, whereby the display is energized whenever a control is operated and is automatically de-energized after the passage of a predetermined amount of time to thus conserve the battery.