| 摘要 |
PURPOSE:To set a pass band frequency of each channel to an optional value within a limited range by constituting plural filters by means of series connections of a variable high-pass filter and a variable low-pass filter each. CONSTITUTION:N-set of channels are provided and each channel consists of a cascade connection of each high-pass fitler (l-N) and each low-pass filter (1'-N') whose cut off frequencies are controlled externally respectively. Frequency components f11-fN2 of a multiplex chnnel signal impressed to an input terminal Tin are separated by the N-set of channel filters and the output is obtained respectively at output terminals T1-TN. Each high-pass filter (n) and each low-pass filter n' consist respectively of a broad hand filter 103 (107), two mixers 102,104 (106,108) and a voltage controlled oscillator (VCO) 101 (105). The VCO 101 supplies a local signal in a frequency fLln to the mixers 102,104 and the VCO 105 supplies a local signal in frequency fL2n to the 'mixers 106,108.
|
