EP 0786093 A1 19970730 - METHOD FOR DETECTING A SIGNAL
Title (en)
METHOD FOR DETECTING A SIGNAL
Title (de)
VERFAHREN ZUR SIGNALDETEKTION
Title (fr)
PROCEDE DE DETECTION D'UN SIGNAL
Publication
Application
Priority
- FI 9500563 W 19951011
- FI 944857 A 19941014
Abstract (en)
[origin: WO9612196A1] The present invention relates to a method for detecting an alternating current signal of a predetermined frequency in a received signal. In order to achieve a simple and easily applicable method, it comprises the steps of feeding said received signal to an input (0) of a switching means (MUX) which comprises several outputs (1 - 4) as well as means for alternately connecting the input to each of said outputs (1 - 4), synchronized by a clock pulse fed to the switching means, feeding a clock pulse to the switching means whereby the clock pulse frequency is chosen so that the input (0) of the switching means is once connected to each output (1 - 4) of the switching means essentially during one cycle of a signal to be detected, filtering the signals obtained from the outputs of the switching means, monitoring the filtered signals, and detecting the presence of a signal to be detected as the voltage level of any of the monitored signals exceeds a predetermined level, or as the voltage difference between two monitored signals exceeds a predetermined threshold level. The invention further relates to a detector circuit.
IPC 1-7
IPC 8 full level
G01R 19/00 (2006.01); H04M 15/00 (2006.01); H04M 19/04 (2006.01); H04Q 1/442 (2006.01); G01R 23/02 (2006.01)
CPC (source: EP)
G01R 19/0007 (2013.01); H04M 15/00 (2013.01); H04M 19/04 (2013.01); H04Q 1/4423 (2013.01); G01R 23/02 (2013.01)
Citation (search report)
See references of WO 9612196A1
Designated contracting state (EPC)
BE CH DE DK FR GB IT LI NL PT SE
DOCDB simple family (publication)
WO 9612196 A1 19960425; AU 3655795 A 19960506; CN 1082666 C 20020410; CN 1162996 A 19971022; EP 0786093 A1 19970730; FI 944857 A0 19941014; FI 944857 A 19960415; FI 99166 B 19970630; FI 99166 C 19971010
DOCDB simple family (application)
FI 9500563 W 19951011; AU 3655795 A 19951011; CN 95196167 A 19951011; EP 95934161 A 19951011; FI 944857 A 19941014