Title:
BAND-PASS FILTER DEVICE
Document Type and Number:
Japanese Patent JP3802968
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To shorten time required for detecting the entire all the frequencies, even if the number of pass frequencies is increased for detecting a signal level by inputting same are signal to two band-pass filter circuits having specified operation clock frequencies.
SOLUTION: Two switched capacitor-type band-pass filter circuits 11A and 11B in identical constitution, which sequentially and circularly switch m-pieces of pass bands and time-divisionally output the level signals of the frequencies of respective pass bands are provided. An identical sound signal is inputted to two measuring circuits 10A and 10B. When the frequency of the operation clock of the filter circuit 11A is set to fc, the frequency of the filter circuit 11B is set be fc' [(m+1)/12].fc. Then, n-th frequency fn in m-pieces of pass frequencies is set to be fn (2+26-m).fn-1 for n-1 th frequency fn-1. N is such that n=2 to m.
Inventors:
Toshiya Takeuchi
Tetsuro Iri
Tetsuro Iri
Application Number:
JP12145097A
Publication Date:
August 02, 2006
Filing Date:
April 25, 1997
Export Citation:
Assignee:
New Japan Radio Co., Ltd.
International Classes:
G01R23/165; H03H19/00; (IPC1-7): H03H19/00; G01R23/165
Domestic Patent References:
| JP7176990A | ||||
| JP5149983A |
Attorney, Agent or Firm:
Tsuneaki Nagao