Title:
METHOD AND DEVICE FOR DETECTING IN-BAND ONE-FREQUENCY SIGNAL
Document Type and Number:
Japanese Patent JP2833879
Kind Code:
B2
Abstract:
PURPOSE: To simply and surely detect a signal by providing two filters, a comparator circuit, a decision circuit, a time protection circuit and a function for utilizing its output signal as a suppression signal and a band stop signal to the in-band one-frequency detection circuit.
CONSTITUTION: A linear PCM signal 10 received from an input terminal 1 is inputted to a one-frequency band pass 'digital filter BPF 2, from which only a 1st signal component is extracted and inputted to a frequency band pass digital filter BPF 3, from which.a 2nd signal component with a 1st signal component eliminated therefrom is extracted. The two extracted signal component levels are compared by a comparator circuit 5, which outputs a signal representing whether difference of the both levels is larger or smaller than a set comparison value. When a difference of levels of both the signals is larger than the setting value, a decision circuit 6 outputs a 1st digital code and when a difference of levels of both the signals is smaller than the setting value, the decision circuit 6 outputs a 2nd digital code. Thus, an in-band one-frequency component is not mis-recognized from a frequency component included in a voice signal.
More Like This:
| WO/1992/005541 | VOICE CODING SYSTEM |
| JPH073976 | [Title of Invention] Digital voice scrambling device |
| WO/2001/065542 | VOICE ENCODING/DECODING DEVICE AND METHOD THEREFOR |
Inventors:
NAKAMURA SHINYA
WAKAO KATSUHIKO
WAKAO KATSUHIKO
Application Number:
JP16055491A
Publication Date:
December 09, 1998
Filing Date:
July 01, 1991
Export Citation:
Assignee:
NIPPON DENKI KK
MYAGI NIPPON DENKI KK
MYAGI NIPPON DENKI KK
International Classes:
H04B14/04; H04J4/00; (IPC1-7): H04J4/00; H04B14/04
Domestic Patent References:
| JP273733A | ||||
| JP2105670A |
Attorney, Agent or Firm:
Yosuke Goto (2 outside)