An introduction system for participating users, includes for each user a personal device that is subject to activation by remote paging. Each user, also has a memory device that contains personal data defining the user by personal characteristics such as traits and interests. A local control unit receives the respective personal data from a plurality of user memory devices and using computer means compares the personal data of each user with the personal data of other users who have within the same time frame entered their personal data into the local control unit via their respective memory devices. Pairs who are matched to predetermined standards by the computer comparison are automatically paged via their personal devices and an introduction is facilitated.

Introduction system for locating compatible persons

An enhanced backscatter RF-ID tag reader system and multiprotocol RF tag reader system is provided. In a multiprotocol mode, the system emits a non-stationary interrogation signal, and decodes a phase modulated backscatter signal by detecting a stronger phase component from quadrature phase representations or determining phase transition edges in a phase of a received signal. The RF tag reader system predicts or follows the phase of the backscatter signal, thereby avoiding interference from nulls in the received signal waveform due to the non-stationary interrogation signal, relative movement or environmental effects. An acoustic RF-ID tag detection system detects the reradiated signal corresponding to respective transformation of a signal in the tag. Detection of either type of RF-ID tags therefore is possible, and the absence of any tag or absence of any valid tag also determined.

Dual mode transmitter-receiver and decoder for RF transponder tags

An electronic monitoring system monitors an individual for compliance with a protective order. When a violation is detected, the system automatically gathers evidence, independent of any that may be provided by the victim of the violation, to establish probable cause of such violation. The monitoring system includes a transmitter tag worn by the individual guilty of the violation (the "abuser") that transmits a unique identifying (ID) signal, either periodically or when triggered. A receiving/monitoring device (RMD), or equivalent, is carried by or positioned near the victim, e.g., in the victim's house and/or place of employment, for receiving the ID signal. A central monitoring computer is located at a central monitoring location that is in selective telecommunicative contact with the RMD. The computer maintains a response file that provides appropriate instructions to personnel or equipment at the central monitoring location or elsewhere in the event an abuser is detected by the victim's RMD, so that appropriate action can be taken in order to electronically gather evidence of the protective order violation, and to protect the victim. A portable electronic monitoring system may be carried or worn by a victim, thereby warming such victim if the abuser comes near the victim, regardless of where the victim may be.

Electronic system and method for monitoring compliance with a protective order

SAW tags were invented more than 30 years ago, but only today are the conditions united for mass application of this technology. The devices in the 2.4-GHz ISM band can be routinely produced with optical lithography, high-resolution radar systems can be built up using highly sophisticated, but low-cost RF-chips, and the Internet is available for global access to the tag databases. The "Internet of Things," or I-o-T, will demand trillions of cheap tags and sensors. The SAW tags can overcome semiconductor-based analogs in many aspects: they can be read at a distance of a few meters with readers radiating power levels 2 to 3 orders lower, they are cheap, and they can operate in robust environments. Passive SAW tags are easily combined with sensors. Even the "anti-collision" problem (i.e., the simultaneous reading of many nearby tags) has adequate solutions for many practical applications. In this paper, we discuss the state-of-the-art in the development of SAW tags. The design approaches will be reviewed and optimal tag designs, as well as encoding methods, will be demonstrated. We discuss ways to reduce the size and cost of these devices. A few practical examples of tags using a timeposition coding with 106 different codes will be demonstrated. Phase-coded devices can additionally increase the number of codes at the expense of a reduction of reading distance. We also discuss new and exciting perspectives of using ultra wide band (UWB) technology for SAW-tag systems. The wide frequency band available for this standard provides a great opportunity for SAW tags to be radically reduced in size to about 1 x 1 mm2 while keeping a practically infinite number of possible different codes. Finally, the reader technology will be discussed, as well as detailed comparison made between SAW tags and IC-based semiconductor device.

Review on SAW RFID tags

An improved automatic/remote RF instrument monitoring system including a plurality of transponders configured to operate with one of a plurality of parameter sensing instruments remotely located from an interrogate/receiver. The interrogate/receiver transmits RF transponder activation signals in the form of a tone modulated onto a carrier. In response to the activation signals, the transponders "wake-up" and transmit an RF transponder signal which is received and processed by the interrogate/receiver. The transponders include a transmission enable circuit which initiates transmission of the RF transponder signals at random times after receipt of the activation signals. The RF transponder signals are formed by a plurality of spaced transponder information packets. Transponder information packets of the transponder signal are transmitted at pseudorandom frequencies as a Manchester encoded bit stream including a preamble field of predetermined preamble data, an instrument parameter field of data sensed by the instrument, an instrument identification field of instrument identification data, and an error control code field of BCH error control code data.

Automatic/remote RF instrument monitoring system

A system for identifying persons and objects includes an information carrier adapted to be secured to an object to be identified, and a read unit coupled to the information carrier by means of electromagnetic waves. The information carrier incorporates a plurality of passive elements interconnected with a receive-transmit antenna system so that an interrogation signal is processed and retransmitted as a unique signature of the information carrier. The passive elements of the information carrier include delay elements, attentuation elements, and filters, interconnected in a plurality of parallel paths to generate the identifying signature.

Apparatus for identifying objects and persons

Radio transmission system in which the carrier frequency oscillator at the transmitter is wobbulated by varying its frequency in a periodic manner and modulated and transmitted to a receiving site where the detected signal is passed through two separate paths, one being supplied to a converter and the other is supplied to the converter through a delay line. The output of the converter comprises an intermediate frequency which contains the modulation which is then demodulated and detected. Modification of the invention provides for transmitting two or more separate intelligences on the carrier and detecting the two intelligences at the receiver.

Radio frequency transmission system

A system is disclosed for synchronizing a free-swinging oscillator to a reference signal of a substantially lower frequency. A regulating circuit connects to the oscillator to control the frequency thereof. A quartz oscillator is provided for producing the reference signal. The reference signal is subsequently connected to a frequency multiplier and/or frequency divider, an amplifier and a pass band filter. An output signal from the pass band filter is fed to a harmonics mixer connected to the free-swinging oscillator and which produces a pattern of harmonics. A selective amplifier feeds an intermediate frequency obtained from the harmonics mixer to the regulator circuit. A filter also connected to the quartz oscillator produces harmonics which are also coupled to the regulating circuit. By phase or frequency comparison the regulating circuit adjusts the running frequency of the free-swinging oscillator.

Arrangement for synchronizing a free-swinging oscillator

A communication transmission system for electromagnetic waves comprising a transmitter, transmitting and receiving antenna with a radio link hop therebetween and a receiver having an associated diversity receiver. When there is no access to energy supply, network energy is supplied from batteries, solar systems and other power supplies which have limited power and are expensive. So as to provide energy saving operation of a system, a digital system is created and the invention provides a fade detector in the receiver for fast recognition of fading and which produces signals corresponding to the weighted switching thresholds that are derived for the connection of the diversity receiver which had previously been disconnected so as to reduce power consumption and for setting by reducing or increasing the transmission power or for the IF through connecting by way of a plurality of radio link hops or for the compensation or cancellation thereof.

Communications transmission system for electromagnetic waves

The invention relates to a communications system for electromagnetic waves which, for the respective transmission direction, comprises a transmitter (S), a transmitting antenna (AS1) and two receiving antennas (AE1, AE2) with an intermediate radio field and a receiver (E) with an associated space diversity receiver (DivE) in which the signals of the two receive arms are converted into a required frequency level, are brought together in a combiner and evaluated and then demodulated. For a communications system of this type, a solution for reliable signal transmission with a minimum bit error rate is intended to be indicated. For this purpose, the invention provides that, in addition to the reception space diversity, the transmission power is divided up and transmitted in-phase and with the same group delay to two antennas (AS1, AS2).

Klaus Dipl.-Ing. Vogel

Papers

Apparatus for identifying objects and persons

Radio frequency transmission system

Arrangement for synchronizing a free-swinging oscillator

Communications transmission system for electromagnetic waves

Communications system with space diversity