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:
May. 27, 1997
Filed:
Oct. 28, 1994
Kenichi Suzuki, Yokohama, JP;
Sakari Ohira, Sendai, JP;
Fujio Sumi, Tokyo, JP;
Osamu Suzuki, Sayama, JP;
Hitachi Denshi Kabushiki Kaisha, Tokyo, JP;
Tohoku Electric Power Co., Inc., Miyagi-ken, JP;
Fuji-Tekku Kabushiki Kaisha, Tokyo, JP;
Abstract
In radio communication system in which single frequency simultaneous transmission and reception is performed, a speech audio signal is divided by a predetermined time interval. A transmission time and a reception time are allotted in the predetermined time. A time-compressed signal is transmitted during the transmission time, and a time-compressed signal transmitted from other transceiver is received during the reception time and it is decompressed to the original length. The transmission time and the reception time are alternately repeated to transmit and receive the audio signals substantially simultaneously by a single frequency, and the audio signal is reproduced from the received signal. When communication with a telephone set is to be established, a DTMF signal is used as a dialing signal to call the telephone set from the transceiver. The DTMF signal is time-compressed and then transmitted along with the speech signal. A transmission timing of the DTMF signal is controlled, and the generated DTMF signal is temporarily stored in a memory. When the transmission of the DTMF signal can be completed before the transmission time is switched to the reception time is determined, and if it can, the DTMF signal is read from the memory and transmitted.