Offset down conversion for a two-handset cordless telephone system

Claim 1

A cordless telephone set, comprising: a first handunit for producing a first audio signal; a second handunit for producing a second audio signal; and a base unit for receiving signals of said handunits, and coupling said signals of said handunits to a telephone system; said base unit including means for combining said received signals of said handunits to form a single output signal for transmission via said telephone system; said handunits and said base unit communicating via a single antenna mounted on said base unit; said first handunit transmitting said first audio signal on a first frequency and receiving on a second frequency; said second handunit transmitting said second audio signal on a third frequency and receiving on a fourth frequency; and in order to provide for a three-way conversation said first audio signal received from said first handunit is transmitted by said base unit to said second handunit, and said second audio signal received from said second handunit is transmitted by said base unit to said first handunit; said base unit employing a first double conversion intermediate frequency arrangement for processing signals received at said first frequency, and a second double conversion intermediate frequency arrangement for processing signals received at said third frequency; said first and second double conversion intermediate frequency arrangements having respective first IF frequency portions, said respective first IF frequency portions being tuned away from a nominal frequency value by a substantially equal amount in opposite directions.