05218343 is referenced by 166 patents and cites 6 patents.

A read/write device includes a transmitter for producing an RF signal and a modulator coupled to said transmitter for modulating the RF signal and, finally a data receiver for receiving RF data signals from a portable microchip. The microchip includes a resonant circuit tuned to the RF frequency of the read/write transmitter and a receiver that is coupled to the resonant circuit for detecting the RF signal. There is also provided a charging capacitor capable of storing the electrical energy from the RF signal so that the microchip can be powered during pulse pauses of the RF signal. The microchip includes a memory circuit for storing the identification code of the microchip, and a code generator that is coupled to the memory circuit for generating an RF signal that is modulated with the identification data. A switching element that couples the resonant circuit to the code generator de-tunes the resonant circuit when the identification data is transmitted back to the read/write device. The same resonant circuit also serves to field program the memory circuit of the microchip by receiving pulse pause modulation signals (PPM) of the RF carrier signal thus allowing the identification code of the microchip to be altered by the read/write device.

Portable field-programmable detection microchip
Application Number
Publication Number
Application Date
February 5, 1991
Publication Date
June 8, 1993
Wilfried Herrmann
Anatoli Stobbe
Steinradweg 3, D-3013 Barsinghausen 1
Collard & Roe
Anatoli Stobbe
G08B 21/00
View Original Source