Abstract: A system and method of determining an available frequency sub-band for radio traffic in a multiple node radio network is disclosed. The method and system provide for communication over a radio frequency band, the radio frequency band comprising radio frequency sub-bands and providing a radio node group of at least one radio communications devices configured to broadcast and receive on the radio frequency band. The system and method create a time for a window of radio broadcast silence on at least one of the radio frequency sub-bands by the radio node group. The system and method survey the at least one of the radio frequency sub-bands during the window of radio broadcast silence. The system and method choose, based on the survey, a radio frequency sub-band for broadcast from the radio frequency band.

Abstract: A process for use in conjunction with a communications network routing protocol that automatically adjusts for congestion that may occur due to the presence of advantaged and partially disadvantaged nodes. The network nodes check to determine if they are advantaged or partially disadvantaged. Advantaged nodes may, for example, be airborne or satellite nodes having a high degree of network connectivity. Partially disadvantaged nodes may comprise nodes that are low on power. Advantaged nodes and partially disadvantaged nodes adjust the network metrics entered into the routing tables they use to advertise their routing information over the network to show longer pathways through such nodes. As a result the other nodes in the network reduce the amount of network traffic routed through advantaged and disadvantaged nodes.

Abstract: A method of disrupting communications reception of a target radio receiver. A plurality of transmitters transmit a noise signal toward the target radio transceiver. Each of the plurality of transmitters has a receiver associated therewith A first transmitter ceases transmitting a noise signal at a pre-determined time. A receiver associated with the first transmitter receives information from another of the plurality of transmitters when the first transmitter has ceased transmitting the noise signal. The first transmitter resumes the transmission of the noise signal after the information has been transmitted.

Abstract: A system and method of determining an available frequency sub-band for radio traffic in a multiple node radio network is disclosed. The method and system provide for communication over a radio frequency band, the radio frequency band comprising radio frequency sub-bands and providing a radio node group of at least one radio communications devices configured to broadcast and receive on the radio frequency band. The system and method create a time for a window of radio broadcast silence on at least one of the radio frequency sub-bands by the radio node group. The system and method survey the at least one of the radio frequency sub-bands during the window of radio broadcast silence. The system and method choose, based on the survey, a radio frequency sub-band for broadcast from the radio frequency band.

Abstract: A digital echo suppression circuit in a four-wire digital telephony circuit having an echo from a local or remote connection to a two-wire circuit or other echo source. The invention incorporates a simple method of using the sample pairs from the first and second sampling circuit to produce a control signal from a control circuit. If the subscriber signal is "louder" than the network signal, then the subscriber signal is passed through. If the network signal is louder than the subscriber signal, the interrupter is activated and a zero level is substituted for the subscriber signal in transmissions toward the network. The invention uses the scheme of comparing instantaneous signal amplitude and using the larger amplitude to set a threshold value. The signal setting the threshold then remains the "loudest" until such time as the other signal can exceed the threshold.

Abstract: A method is disclosed for demodulating binary differential phase shift keyed signals in the presence of carrier frequency uncertainties. In phase modulation, a data signal is impressed on a carrier frequency to produce a modulated signal. The modulated signal and a corresponding quadrature signal are input to a split delay line, wherein each half of the delay line provides a delay of one-half the data signal bit period. The modulated and the delayed signals are input to a summing junction to provide a combined output independent of the carrier frequency. Thus, the method of demodulation is insensitive to Doppler shifts and other carrier frequency offsets.

Abstract: A packet switching module connects to a multiplexed carrier line which has at least an input line and an output line. A receiver circuit receives an information frame over the multiplexed carrier line. The information frame has a predetermined format which includes a physical destination address. A plurality of processing modules and a controller are connected to a common memory and switching the packets according to the destination addresses. The new information frame is outputted on the multiplexed carrier line by a transmitter circuit.

Abstract: A method is provided for searching a wide, high-noise frequency band for a narrow, phase-modulated signal to determine the approximate carrier frequency of a data signal. The method comprises the steps of sampling a received signal at a rate sufficiently high to cover the search bandwidth, performing an efficient Fourier transform on the sampled signal to obtain a discrete point power spectral density, filtering each frequency component of the power spectral density with averaging filters, analyzing the filtered components to find the area of greatest power concentration, and computing the center frequency of the area of greatest power concentration. The method determines the approximate carrier frequency of a data signal quickly and efficiently for use in starting or detecting loss of lock in a frequency-locked demodulator.

Abstract: An analog echo suppression circuit is used with a telephony 2-wire circuit to 4-wire circuit interface. The 2-wire circuit carries a first signal and the 4-wire circuit carries a second signal. Each circuit has an input port and an output port. The interface produces an echo signal on the output of the 2-wire circuit when the second signal is received at the input port of the 2-wire circuit. A first communication channel connects the output of the 4-wire circuit to the input of the 2-wire circuit. A second communication channel connects the output of the 2-wire circuit to the input of the 4-wire circuit and series analog switches or transmission gates can interrupt the second channel. A comparator circuit receives the first and second signals from the first and second channels and has first and second outputs.

Abstract: Two identical and interconnected switch matrices are used wherein one is "on-line" and the other is "off-line". If an individual module in the on-line switch fails, an identical module in the standby matrix is switched in to carry traffic. The failed module can then be replaced with an operable unit. The feature of modularity not only greatly enhances the performance of the switch matrix but also provides for quick restoration of the switching apparatus to a preferred configuration of operability.

Abstract: The elastic storage circuit disclosed permits insertions and deletions to be made as required without disturbing the operation of a downstream framing circuit by inserting or deleting exactly the amount of data contained in the period of the framing indicator. In particular in certain instances with certain types of framing circuits and certain types of framing indicators the same effect may be accomplished by inserting or deleting a quantity of data equal to one-half the period of the framing indicator. The use of the elastic storage circuit described herein permits the required insertions and deletions to be made in the data without throwing the framing circuit out of frame. Thus only the data actually inserted or deleted is lost and the much longer and more extensive loss of data which occurs during a reframe is avoided.

Abstract: The method of and apparatus for synchronizing all local oscillators in a multinode communication system is disclosed wherein each local oscillator is synchronized to the average frequency of some or all incoming signals from neighboring nodes. This is accomplished by detecting the difference in frequency between the local oscillator and the frequency of incoming signals, averaging these differences, and using the average to adjust the local oscillator. The frequency difference is measured over a period of time and the accumulated difference over the period is checked for reasonableness prior to use. Its use is further delayed after the period of measurement by a period of time while the incoming link is monitored for signal problems which might have occurred toward the end of the accumulation period and which therefore would not have been detected by an immediate reasonableness check.

Abstract: A method and apparatus for providing improved telephonic conferences is presented. A speaker is selected for each conferee from the signals of the other conferees. The peak values of the speaker signal establish a variable reference level which another conferee must first exceed in order to become the new speaker and establish a new reference level. The reference level is continuously allowed to decay so that new speakers may gain the floor when the current speaker's peak signals fall below the peak signals of another speaker. Both an analog and a digital embodiment of the invention are presented. A specific feature of the invention involves directing all signals of other conferees to all conferees and each conferee station selects the loudest signal (maximum amplitude) for that conferee.

Abstract: A method and apparatus for providing improved telephonic conferences is presented. A speaker is selected for each conferee from the signals of the other conferees. The peak values of the speaker signal establish a variable reference level which another conferee must first exceed in order to become the new speaker and establish a new reference level. The reference level is continuously allowed to decay so that new speakers may gain the floor when the current speaker's peak signals fall below the peak signals of another speaker. Both an analog and a digital embodiment of the invention are presented.