Abstract: A printed circuit board (PCB) transceiver I/O filter design which provides both polarization and isolation filtering includes a receive probe positioned in a first orientation in an opening of the PCB which has a feed waveguide attached to it on a first side of the PCB. Receive signals propagate into the feed waveguide and excite the probe causing the receive probe to couple the received signals to receive circuitry. The transceiver design further includes an enclosed waveguide structure attached to the PCB having a first end positioned over the PCB opening and a second end positioned over a transmit probe which is positioned in a second orientation orthogonal to the receive probe. The transmit probe is excited by transmit circuitry and couples signals into the waveguide structure through the PCB opening and out the feed waveguide.

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 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.