Title:
FILTER CIRCUIT
Document Type and Number:
Japanese Patent JPH01143517
Kind Code:
A
Abstract:
PURPOSE:To obtain a filter circuit in response to the operation in the multi- mode without increase in the number of circuits by providing an oscillator varying a clock frequency depending on various transmission/reception modes and supplying its output to a switched capacitor filter circuit. CONSTITUTION:A transmission BPF 61, a reception LPF 62 and a reception HPF 63 constitute a switched capacitor circuit 6, which is operated by clocks of frequencies f1-f3 from a clock oscillator 9. The cut-off frequency fCH of the reception HPF 63 is proportional to the clock frequency f3 from the oscillator 9. Moreover, the cut-off frequency fCL of the reception LPF 62 is proportional to the clock frequency f2 from the oscillator 9. Thus, the clock frequencies f2, f3 are varied so as to make the cut-off frequencies fCH, fCL of each filter variable thereby setting optionally the bands fCH-fCL of the filter circuit. Thus, the filter circuit in response to the various transmission/reception modes is easily obtained.
Inventors:
HIROSE YUKIKAZU
YAGO MASATOSHI
NAKATSUKA JUNJI
YAGO MASATOSHI
NAKATSUKA JUNJI
Application Number:
JP30223187A
Publication Date:
June 06, 1989
Filing Date:
November 30, 1987
Export Citation:
Assignee:
MATSUSHITA ELECTRIC IND CO LTD
International Classes:
H03H19/00; (IPC1-7): H03H19/00
Domestic Patent References:
| JPS62209913A | 1987-09-16 | |||
| JPS5767312A | 1982-04-23 | |||
| JPS59175209A | 1984-10-04 |
Attorney, Agent or Firm:
Akira Kobiji (2 outside)