Abstract: A cable converter produces a 4.5 MHz intercarrier sound signal from a received television signal for application to one input of a phase lock loop circuit, the other input of which is supplied from a voltage controlled oscillator producing a regenerated 4.5 MHz intercarrier signal. The output of the phase lock loop is supplied through a loop filter to the input of the voltage controlled oscillator to control its frequency. The regenerated 4.5 MHz intercarrier signal is thus stabilized by the received 4.5 MHz intercarrier signal.

Abstract: A means for coding and decoding video signals by the application of one of a plurality of available scrambling signals includes means for comparing the brightness level during a predetermined time period of the video signal with the brightness level of the video signal over the succeeding predetermined time period. There are means for changing from one scrambling signal to another if the difference between brightness levels in successive predetermined time periods exceeds a given value.

Abstract: A converter/decoder for use in subscription television includes means for converting any input TV channel to a predetermined output channel. Decoding means are connected to the converter at its output for decoding the selected output channel. The decoder is enabled in response to data carried on the TV signal which describes the program level of the particular selected channel. The means for enabling the decoder includes a comparison circuit which compares the television signal program level data with authorization data and performs an enabling function when there is correspondence between the two data entries. The authorization data may be received by the converter/decoder simultaneously with the program level data, but at a frequency other than that of the television signal, for example, at a frequency in the FM band.

Abstract: A holder for a plurality of dry cells comprises a tray having a pair of open-top compartments, each receiving a plurality of batteries arranged in series and biased into engagement with one another by a contact spring. A retainer projects over each compartment from a common side wall of the compartments and prevents certain batteries from being removed from their normal positions through the open tops of the compartments, while permitting such removal of other batteries. Sufficient lateral clearance is provided to permit the batteries to move somewhat in response to mechanical shock forces without breaking a desired electrical contact.