GB1349923A - Circuit arrangements for producing two closely spaced frequencies - Google Patents

Abstract

1349923 Multiple frequency generators MARCONI CO Ltd 11 Jan 1973 [28 April 1972] 19774/72 Heading H3F A circuit arrangement for producing two output frequencies closely spaced by a small frequency difference comprises an oscillator 3 resonant at a frequency f 0 , an oscillator 6 resonant at a frequency #f equal to half the required frequency separation of the two output frequencies, means, i.e. mixers 4, 5 for mixing outputs from the two oscillators, means, i.e. filters 7, 10 for selecting the upper and lower sidebands resulting from the mixing, means, i.e. mixer 8 for mixing the selected upper side band with output from a multiplier 9 of multiplication factor N having an input derived from the output of the first oscillator 3, means, i.e. filter 12 for selecting from the output of the latter mixer 8 an upper sideband centred upon the frequency (N + 1)f 0 +#f, means, i.e. mixer 11 for mixing the selected lower sideband with output from a multiplier of multiplication factor N having an input derived from the first oscillator 3, and means for selecting from the output of the last mixer 11 a frequency (N+1)f 0 -#f, (N+1)f 0 +#f and (N+1)f 0 -#f being the required two output frequencies. The arrangement is intended for use in a diversity system.