Patent ID: 6714263
Filing Date: 2004-03-30
Classification: H03D,H04B

Abstract:
A multiple conversion tuner, comprising: N cascade-connected frequency changers, each having an output, where N is an integer greater than one and each ith one of said frequency changers comprises a mixer and a local oscillator, where 0(i) a desired signal is converted to an Nth intermediate frequency at said output of an Nth of said frequency changers; (ii) a frequency band occupied by said desired signal at said output of each jth one of said frequency changers is within said passband of each jth one of said intermediate frequency parts of said tuner; and (iii) there is no signal at a frequency Fi in an input spectrum of said mixer of each ith one of said frequency changers such that: IFi-Bwi2&leq;&LeftBracketingBar;Fi&PlusMinus;Fs&RightBracketingBar;&leq;IFi+Bwi2where IFi is an ith intermediate frequency to which said desired signal is converted, Bwi is a bandwidth of said desired signal at said output of each ith one of said frequency changers and Fs is a frequency of any component signal which is generatable by non-linear mixing of any combination of output signals of said local oscillators of said N frequency changers.