Abstract: Channel use in a wireless communication system is monitored for each radio frequency channel spanning a broad allocated bandwidth simultaneously. A transmission having signals in channels spanning the bandwidth is broadband downconverted in analog before being transformed to produce an instantaneous representation of signal levels in each channel. The instantaneous representation is stored. In addition, a statistic characterizing historical use of at least one of the channels in the bandwidth is calculated from the instantaneous representation.

Abstract: A communication system having a communication network, such network having a plurality of communication paths interconnected at various nodes of the network. A plurality of subscriber units is adapted to exchange information through the network. A computer is provided having a processor and a memory, such memory being adapted to store programs to enable the processor to control the information exchange among the plurality of subscriber units. The memory stores an operating system and at least one applications program, the operating system being adapted to manage interfacing between the application program and the system. One of the application programs enables the processor to convert a modulation format of one of the subscriber units into another information transmission protocol of the network.

Abstract: An analog signal is converted to a digital signal by two analog-to-digital converters. The first converter digitizes the analog signal to produce a first series of samples of the signal. The second converter digitizes the analog signal after it has been shifted in phase by 180 degrees to produce a second series of samples. A digital adder then subtracts the second series of samples from the first series to produce the digital signal.

Abstract: A mixer converting a frequency of an input signal to an intermediate frequency has an input port receiving an input signal oscillating at a signal frequency and a sinusoidal pump wave oscillating at a pump frequency. A diode is connected between an input network linked to the input port and an output network linked to an output port of the mixer. The output network and the input network together cause the diode to switch rapidly between ON and OFF states and behave as with square wave drive. Bias circuitry connected to the diode comprises a resistor connected to receive a DC component of current from the diode, the current through the resistor solely biasing the diode.

Abstract: A method and apparatus for monitoring the resonant frequency and absorption level at resonance of an absorption type resonant cavity which involves providing a voltage controlled oscillator, applying to the control input of the voltage controlled oscillator a control signal having a main component V.sub.m and a dither component V.sub.d, splitting the output signal from the voltage controlled oscillator into a portion directed along a test path and a portion directed along a reference path, the reference path including an attenuator controlled by a voltage signal V.sub.k, directing the signal in the test path through the resonant cavity, splitting the signal emerging from the resonant cavity into a portion directed along a frequency detection path and a portion directed along a level detecting path, using the signal directed along the frequency detection path for generating a signal for changing the amplitude of V.sub.

Abstract: A circuit for mixing first and second rf signals to produce an output signal containing a beat frequency comprises a pair of switches each of which has a four diode bridge controlled by the first rf signal. The first rf signal is coupled to a balanced current divider with common mode signal rejection. Load resistors coupled to the bridges provide matched termination of the first rf signal irrespective of the conductive state of the bridges. The value of the resistors and the characteristic impedance of the drive circuit is related to the characteristics of the diodes utilized to maximize the dynamic range of the mixer. Circuitry is provided for coupling all diodes of each bridge in series with respect to the average dc component of the first rf signal and to properly terminate the average dc component. The two diode bridges are conductive and non-conductive in opposing half cycles of the first rf signal.

Abstract: A circuit for mixing first and second rf signals to produce an output signal containing a beat frequency comprises a pair of switches each of which has a four diode bridge controlled by the first rf signal. The first rf signal is coupled to a balanced current divider with common mode signal rejection. Load resistors coupled to the bridges provide matched termination of the first rf signal irrespective of the conductive state of the bridges. The value of the resistors and the characteristic impedance of the drive circuit is related to the characteristics of the diodes utilized to maximize the dynamic range of the mixer. Circuitry is provided for coupling all diodes of each bridge in series with respect to the average dc component of the first rf signal and to properly terminate the average dc component. The two diode bridges are conductive and nonconductive in opposing half cycles of the first rf signal.