Abstract: A wireless local area network includes a radio transmitter/receiver for transmitting and receiving in accordance with the FCC rules for the ISM band. The receiver/transmitter supports spread spectrum frequency hopping in the 2.4 GHz ISM band and can be tuned to one of e.g. 82 different frequencies spaced at 1 MHz intervals. The radio transmitter/receiver is a low cost, low power, small size unit located on a printed circuit board in a PCMCIA form factor. Third order mixers are used in combination with a switched prescaler for a low cost and compact frequency control system capable of rapid switching of the radio between transmitting and receiving functions. No special shielding is needed between the frequency control circuitry and the receiver IF circuitry.

Abstract: A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ("FM") signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ("RF") signal source for the transmitter and the local oscillator "LO") signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal.

Abstract: A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ("FM") signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ("RF") signal source for the transmitter and the local oscillator ("LO") signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal.

Abstract: A full duplex data transceiver for transmitting and receiving frequency-modulated ("FM") signals representing binary data includes separate transmit and receive antennas, and a single oscillator which serves as both the radio frequency ("RF") signal source for the transmitter and the local oscillator ("LO") signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the transmit antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal. During signal reception, the oscillator output, in the form of the transmitted FM signal, is received via the receive antenna along with a FM receive signal for mixing therewith to down-convert the FM receive signal.

Abstract: A full duplex data transceiver for transmitting and receiving trinary frequency-modulated ("FM") signals representing binary data includes at least one antenna and a single oscillator which serves as both the radio frequency ("RF") signal source for the transmitter and the local oscillator ("LO") signal source for the receiver. During signal transmission, the oscillator output is frequency-modulated to provide a FM transmit signal to the antenna. The oscillator output is frequency-modulated with binary transmit data by modulating an error feedback signal which serves as the control voltage for a voltage-controlled oscillator in a phase-lock-loop, thereby producing the FM transmit signal.

Abstract: A spread spectrum communications system includes an encoder for differentially encoding a spread spectrum spreading code sequence in accordance with an input data signal. Each chip of the spreading code sequence is inverted, or not inverted, relative to the polarity of a corresponding chip of the spreading code sequence a fixed time delay previously, depending on whether the input data is a logic one or zero, respectively. At the receiver, the data is recovered in a differential data decoder wherein the presently received chip of the spread spectrum signal and a corresponding previously received chip of spread spectrum signal, received a fixed time delay previously, are compared one chip at a time. Since it is the spreading code sequence that is differentially encoded and differentially decoded, there is no need for a synchronized code sequence generator at the receiver, and data synchronization is achieved after one cycle time of the received spread spectrum spreading code sequence has elapsed.

Abstract: A multiple phase PSK demodulator for use in a spread spectrum communication system includes a plurality of baseband frequency converters coupled to a corresponding plurality of differential decoders in order to directly recover the encoded PSK data. The logic outputs of the plurality of differential data decoders are coupled to a majority vote logic circuit for determining the correct logic level output signal of the plurality of differential data decoders. In another embodiment, a three phase resistive network is used to convert the two phase quadrature output of two baseband frequency converters to plural phase outputs coupled to the inputs of a corresponding plurality of differential data decoders.

Abstract: A code division multiplex system for use in a spread spectrum communication system utilizes selectable length spread spectrum spreading code sequences. At the encoder, one of a pluraluty of a spread spectrum spreading code sequences having a given fixed length is selected for differential encoding in accordance with the input data to be transmitted. At the receiver correlator, a selectable length differential decoder is set to be responsive to a spread spectrum spreading code sequence having a length substantially equal to the length of the encoded spread spectrum spreading code sequence.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units each include a radio transmitter and a radio receiver. Also included in the base unit is bimodal tuned circuit operable as a filter and as an oscillator.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units each include a radio receiver and a radio transmitter. Also included in the remote unit is a modulator connected to said remote unit radio transmitter and circuitry limiting the amplitude of the modulated signals produced by said transmitter. A dialing circuit connected to said modulator causes the amplitude of each outgoing dial pulse to be transmitted at a level substantially higher than when no dial pulses are present.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Included in both the base and extension units are a radio receiver and a radio transmitter. Also included in the remote unit is a bimodal tuned circuit operable as both a filter and as an oscillator.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units each include a radio receiver and a radio transmitter. The remote unit transmits tone signals of a first amplitude for line seizure and of a second amplitude for line pulsing in response to manually initiated dial pulses. A dial pulse detection circuit at the base unit differentiates between the two types of pulses breaking connections to the telephone line in response to incoming dial signals of the second amplitude.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units each include a radio receiver and a radio transmitter. Also included in the remote unit is a modulator connected to the radio transmitter and circuitry limiting the amplitude of modulated signals produced by said transmitter. A dialing circuit connected to the modulator causes the amplitude of each outgoing signal representing a dial pulse to be transmitted at a level substantially higher than when no dial pulses are present. At the base unit a dial pulse detection circuit differentiates between the modulated signals received by the associated radio receiver, providing connections to the telephone line in response to signals of a first amplitude and breaking the line in response to each received pulse of a higher level amplitude.

Abstract: A wireless extension telephone system including a base unit connected to a telephone line and a remote extension unit. Both base and remote units including a radio receiver and a radio transmitter. Also included in both base and remote units is a bimodal tuned circuit operable as a filter and operable as an oscillator.