The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 19, 1999
Filed:
Feb. 20, 1997
Kenji Irie, Kanagawa, JP;
Yoshihiro Nakamura, Kanagawa, JP;
Sony Corporation, Tokyo, JP;
Abstract
A signal detection circuit includes band pass filters for detecting frequency components of a Call Alert signal (CAS) signal, a tone detection circuit for detecting whether or not a signal component is present in the output signals of the band pass filters, and two types of guard time setting circuits that have different guard times. When the CAS signal component is present, a transmitting speech signal is muted. Thereafter, with the guard time setting circuit having the normal guard time, it is determined whether or not the signal component lasts for a predetermined time period. Since the CAS signal is detected with two types of guard times, even if the transmitting speech signal contains a frequency component of the CAS signal, the transmitting speech signal is not mis-detected as the CAS signal.