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:
Oct. 27, 1987
Filed:
Oct. 31, 1985
Anthony J Rossetti, San Jose, CA (US);
Paul A Nysen, Sunnyvale, CA (US);
X-Cyte, Inc., Mountain View, CA (US);
Abstract
Interrogator/receiver apparatus is disclosed for transmitting a first signal to, and receiving a second signal from a remote transponder. In the preferred embodiment, the transponder is a passive, surface acoustic wave device which receives the first signal, processes this signal and transmits, in reply, the second signal which includes a unique identification code. The interrogator/receiver apparatus includes (1) a common RF unit for generating the first (interrogation) signal and (2) a plurality of transmitter/receiver heads, each remote from, and coupled to the common signal generator, for transmitting the first signal to, and receiving the second signal from a transponder or transponders in its vicinity. Advantageously, each transmitter/receiver head includes a signal mixer which performs four quadrant multiplication of the first signal by the second signal to produce a third, audio frequency signal containing frequencies equal to the instantaneous difference between the frequencies of the first and second signals. One of the mixer inputs is coupled to the RF transmission line connected to the common RF signal generator, or to a transmit amplifier connected to the transmission line; the other mixer input is connected to a directional coupler that, in turn, is connected to a common transmit/receive antenna. This directional coupler operates to pass the first signal from the transmission line, or transmit amplifier, to the antenna and to pass the second signal from the antenna to the mixer.