Abstract: A dual channel transceiver which operates at two different frequencies and which may be used in a network using older transceivers operating at a single frequency is disclosed. A pilot tone is transmitted by the transceiver when it is using the second channel to cause the older transfers to remain synchronized and thereby prevent them from transmitting data which would otherwise interfere with the data on the second channel. The relative magnitude of the signals on both channels is compared to prevent the detection of cross-talk on the second channel as data.

Abstract: A receiver for detecting spread spectrum binary data particularly on a power line in the presence of channel distortion. In one embodiment a standard pattern ideally suited for minimal distortion in the channel is used in conjunction with an alternate pattern which is developed to better detect carrier and data in the presence of certain channel distortion. The receiver switches between the standard and alternate pattern to provide improved detection. In another embodiment an adaptive pattern is used which is developed from the receive signal. For instance, the signal over several bit times is averaged to provide a pattern which is correlated with a receive signal.

Abstract: A “hint” signal is developed which points to suspected erroneous bits in received data by examining anomalies in the signal. More particularly, a delta phase pointer which quantifies one of the anomalies is used. The realigning of an IQ pointer provides an additional anomaly which is prioritized along with the delta phase pointer. The particular error correcting code used for the power line application provides seven check bits for a data byte and permits the correction of up to two errors. A third error is correctable through use of the hint signal and a parity bit.

Abstract: A receiver for detecting spread spectrum binary data particularly on a power line in the presence of channel distortion. In one embodiment a standard pattern ideally suited for minimal distortion in the channel is used in conjunction with an alternate pattern which is developed to better detect carrier and data in the presence of certain channel distortion. The receiver switches between the standard and alternate pattern to provide improved detection. In another embodiment an adaptive pattern is used which is developed from the receive signal. For instance, the signal over several bit times is averaged to provide a pattern which is correlated with a receive signal.

Abstract: A module for interconnecting an AC power line to a load such as a lamp, which includes a first switch. The module detects the state of the first switch and then provides power to the load when the switch is closed. Sequentially opening and closing the first switch can be used as a command to dim the lamp. The module may also include a transceiver which communicates the state of the switch to the other modules thereby allowing a plurality of devices to be controlled by the first switch.

Abstract: A receiver for detecting spread spectrum binary data particularly on a power line in the presence of channel distortion. In one embodiment a standard pattern ideally suited for minimal distortion in the channel is used in conjunction with an alternate pattern which is developed to better detect carrier and data in the presence of certain channel distortion. The receiver switches between the standard and alternate pattern to provide improved detection. In another embodiment an adaptive pattern is used which is developed from the receive signal. For instance, the signal over several bit times is averaged to provide a pattern which is correlated with a receive signal.

Abstract: A robust encoding and decoding system of the present invention for communicating binary information using angular modulation system is disclosed. Binary information to be transmitted is data words consisting of 8 data bits, a parity bit, and two additional coding bits at the end of the data word. A transmitter transmits the data words using a binary phase-shift keying (BPSK) modulated signal. The receiver compares the phase of incoming BPSK modulated signal against a local reference signal and records the phase characteristics of the BPSK signal. The receiver also records the amplitude of the recovered data signal. The receiver demodulates and decodes the BPSK signal using a rotating frame of reference that tracks the current phase of the recovered data signal. The receiver tests the parity bit of each word to detect errors. If an error is detected, the receiver attempts to correct the error using the record phase and amplitude information.

Abstract: A power line communications analyzer (PLCA) provides a signal strength metering system and selectable signal attenuation functions for adjusting the transmitting unit's attenuation and measuring error rate without the need for a user to be present at both the sending and receiving locations under test. Each PLCA is coupled to a power line communication network via an electrical outlet and power lines. In actual operation, one of the PLCAs acts as a data transmitter and the other PLCA acts as a data receiver. The mode of operation of the PLCA can be dynamically altered during operation of the system. The PLCA comprises control logic that receives command inputs from a keypad, generates data packets for transmission on the power line communication network, receives and analyzes data packets received from the power line communication network, detects the power line signal and/or noise level and drives the LED display accordingly, and displays packet transmission information on an LCD display.

Abstract: A receiver for detecting spread spectrum binary data particularly on a power line in the presence of channel distortion. In one embodiment a standard pattern ideally suited for minimal distortion in the channel is used in conjunction with an alternate pattern which is developed to better detect carrier and data in the presence of certain channel distortion. The receiver switches between the standard and alternate pattern to provide improved detection. In another embodiment an adaptive pattern is used which is developed from the receive signal. For instance, the signal over several bit times is averaged to provide a pattern which is correlated with a receive signal.

Abstract: A power supply for a node that transmits data onto a power line. A DC supply and capacitor supply power to the node where the output current of the DC supply may be less than required for transmission by the node. When the voltage on the capacitor drops to Vmin transmissions are stopped allowing the capacitor to recharge. A timing circuit is used to determine when to begin transmission to compensate for variables in the node such as line voltages and part tolerances.

Abstract: A power supply for operating from a switched leg of an AC power line and for powering a transmitter is described. A switch provides current during the beginning of each AC half cycle to an inductor and charges a capacitor. When the switch is open, the inductor continues to charge the capacitor. During the time that the inductor is coupled to that AC line, the switched leg is open. For instance, the signal used to close the switch also prevents a triac in the switched leg from conducting. When the voltage on the capacitor drops to a predetermined level transmission from the transmitter is inhibited. A timing circuit is used to determine when to begin transmissions to compensate for variables in the node such as line voltages and part tolerances.

Abstract: A method and apparatus for compensating for distortion in a spread spectrum communications system particularly useful where the spread spectrum is transmitted over a power line. The information carrying signal (ICS) is split into two sub-bands and the ICS in one sub-band (or a correlation value determined from the ICS in that sub-band) is delayed relative to the other sub-band. The ICS (or correlation values) from the two sub-bands are recombined after the delay and processed in an ordinary manner. The time delay is selected so as to compensate for the distortion. In one embodiment, the correlation peaks in each of the sub-bands are examined and the time delay is determined by, in effect, aligning the peaks in the two sub-bands in time so that when the two sub-bands are combined, a sharper correlation peak is obtained.

Abstract: In a communications system, an apparatus and method for detecting a valid signal from noise. An adaptive threshold is used to qualify a received signal. The adaptive threshold is set according to the number of false detects occurring within a given time interval. The number of false detects is initially determined by a quick qualification process. This initial number is subsequently adjusted by a more accurate qualification process. The transmitted signal is modulated with a particular pattern. Upon receiving the signal, it is demodulated to retrieve that pattern. The demodulated pattern is correlated against multiple reference patterns and combined to provide a measure of peak correlation that is independent of pattern phase. Furthermore, a tone detector is used to distinguish valid signals from interfering tones. Two different types of detection methods are performed in parallel. One is based on the energy of the received signal, whereas the other is based on the correlation of the received signal.

Abstract: An apparatus for reducing power line communication signal attenuation is disclosed. This apparatus provides for reduction of power line communication signal attenuation by balancing reactance between chosen circuit elements and the typical impedances found in a house, structure, or similar entity. The present invention uses a series resonant circuitry to couple the communication signal to the power line. The inductance in the series resonant circuitry is chosen to compensate for the de-tuning effect of the typical power line to which it's coupled in the communication system.

Abstract: A sigma-delta A/D converter having a digital logic gate core. The converter is comprised of a loop filter for shaping the converter's quantization noise spectrum. The loop filter is comprised of an unbuffered CMOS logic gate inverter which can be implemented by a gate array. A quantizer is coupled to the loop filter. A logic gate buffer is configured as a one-bit comparator, which is used to perform the quantization. This logic gate buffer can be one of the gates of a gate array. A sampler is coupled to the quantizer for sampling the quantized signal. This sampler can also be implemented by digital circuitry of a gate array. The signal from the sampler is fed into a decimator. The decimator outputs a digital signal representative of the amplitude of the analog signal.

Abstract: An apparatus for snubbing or blanking digital signals representing a band of signals that includes an encoded carrier signal transmitted over a power line. An average signal level is compared with the instantaneous signal level to develop a blanking circuit control signal. Additionally, snubbing occurs in the circuit which determines the average signal level to prevent noise from building-up the average signal level. A hold-off signal is used in this circuit to prevent the average signal level from being latched permanently low. A unique infinite impulse filter subtracts out the D.C. offset thereby improving the dynamic range of the blanking. Additionally, the average signal level is used by AGC logic to control the gain at the front end of the apparatus. The state and switching of the AGC is controlled to minimize errors.

Abstract: An improved transceiver for power line communication using a spread spectrum signal. The amount of correlation for each bit in a word is determined. If a parity error occurs, the state of the bit with the weakest correlation is changed.

Abstract: A power line communication (PLC) apparatus wherein a carrier is derived to avoid determinable interference harmonics. In order to transmit data on a power line containing the television interference or other determinable interference harmonics, the present invention uses redundant carriers at a frequency between the television interference harmonics. In the preferred embodiment, the first carrier is positioned at 118 KHz and the redundant carrier is positioned at 133.7 KHz for the PLC apparatus designed for use in the United States. Other carrier frequencies are used for other countries in order to avoid interference harmonics at a slightly different frequency. The present invention includes a waveshaping and modulation circuit for generating the modulated data waveform for output over the power line. In the preferred embodiment, the waveshaping and modulation circuit includes a waveshape ROM for storing samples that represent the appearance of the carrier waveshape.

Abstract: A method and means for for recovering data in a spread spectrum communications system. The present invention includes a method and means for providing a sync window time period. The sync window is set to encompass the correlation values which are generated one baud time from the previous recovered data bit. The present invention also determines the peak correlation value within the sync window and the location in time within the sync window that the peak correlation value occurs. The present invention also provides a polarity window time period. The polarity window occurs during the sync window. The present invention decodes the data according to the direction of the peak correlation and whether the peak occurred within the polarity window. The sync and polarity windows are then set to occur, such that the peak correlation of the next baud falls within the next instance of the sync window. In this way, data can be recovered continuously.

Abstract: In a power line communication apparatus, data is redundantly transmitted on a first and a second carrier where the carriers are separated by a predetermined number of Hz. In the receiver two channels are used, one for each of the carriers. The noise level in each channel is independently determined. A switching network is used to allow the selection of the channel with the lesser noise or if the noise is approximately equal in both channels, the signals in the channels are combined.