A reference signaling scheme is provided that is based on the use of a Zadoff Chu sequence with cyclic repetition, optionally code division multiplexing precoding, together with frequency domain spectral shaping (FDSS). A specific pulse shape design for the FDSS part of the reference signal scheme in some embodiments involves the use of a raised cosine pulse raised to the power of β. The new solution for generating reference signals has a Low peak average power ratio that matches the PAPR of SC-OQAM, good channel estimation performance, and the ability to implement CDM in the frequency domain to increase multiplexing gain.

A system for selecting an equalizer setting of an equalizer to equalize signals received via a communications link. Starting with a first (e.g., minimum) equalizer setting and a threshold voltage near the mid-eye voltage of the equalized output signal, the system estimates the amplitude of the inner eye of the equalized output signal by comparing the equalized output signal to a series of threshold voltages. If the amplitude of the equalized output signal is less than ideal, the system dynamically increases the equalizer setting. The system quickly converges on the equalizer setting for the communication link because, rather than comparing the output signal at every voltage offset using every equalizer setting, the system only evaluates the equalizer settings necessary to select the equalizer setting for the communications link and uses only the voltage offsets necessary to evaluate each equalizer setting.

Systems and methods which use adjunct signals from a remote highly stable clock to enhance performance of a digital wideband receiver equipped with a less stable local clock system. The digital wideband receiver includes an analog-to-digital converter (ADC) and an adjunct receiver system connected to the output of the ADC. The adjunct receiver system includes matched filters and circuitry configured to generate an interpolation coefficient vector based on the matched filter outputs. The adjunct receiver system further includes an interpolating filter which is configured to remove jitter from the digitized samples output by the ADC using the interpolation coefficient vector.

Embodiments of a gain control circuit and a wideband communication circuit that uses the gain control circuit are disclosed. In an embodiment, gain control circuit includes first and second output terminals to output gain control signals and first and second diode-connected transistors connected between a supply voltage and the first and second output terminals, which are connected to input terminals of a communication component circuit with a plurality of input transistors. The gain control circuit further includes a current digital-to-analog converter connected to the diode-connected transistors to generate first and second currents for the diode-connected transistors based on an N-bit input code, wherein a ratio of the first and second currents sets voltages of the gain control signals that are output from the gain control circuit to the communication component circuit to control signal gain provided by the communication component circuit.

A signal analysis apparatus includes a first frequency conversion unit 10 that generates an intermediate frequency signal S.sub.IF2 and a second spurious signal S.sub.SP2 from a measured signal S.sub.RF of a frequency f.sub.RF (center frequency f.sub.c), and a second frequency conversion unit 25 that converts the intermediate frequency signal S.sub.IF2 and the second spurious signal S.sub.SP2 into an intermediate frequency signal S.sub.IF2′ of a frequency f.sub.IF2′ and a second spurious signal S.sub.SP2′ of a frequency f.sub.SP2′ by performing frequency shift of the intermediate frequency signal S.sub.IF2 and the second spurious signal S.sub.SP2 by a frequency shift amount Δf, in which the frequency shift amount Δf is a value that does not establish a relationship of −W/2≤f.sub.SP2′−f.sub.IF2′≤+W/2.

A radio communication apparatus comprises a spreading unit and a transmitting unit. The spreading unit spreads an ACK/NACK signal or a CQI signal with a sequence defined by one of a plurality of cyclic shift values. The transmitting unit transmits the ACK/NACK signal or the CQI signal. In each symbol that forms the ACK/NACK signal or the CQI signal, the spreading unit uses one of first cyclic shift values, which form a portion of the plurality of the cyclic shift values and which are adjacent to each other, for the ACK/NACK signal, and uses one of second cyclic shift values, which are not within the portion of the plurality of the cyclic shift values, for the CQI signal. At least one cyclic shift value that is cyclically subsequent to the first cyclic shift values or the second cyclic shift values is not used for either the ACK/NACK signal or the CQI signal.

An intelligent backhaul radio that has an advanced antenna system for use in PTP or PMP topologies. The advanced antenna system includes a plurality of directional antenna arrays, wherein each directional antenna array includes a plurality of directional antenna sub-arrays, and wherein each directional antenna sub-array includes a plurality of directional antenna elements. At least one of the plurality of directional antenna arrays includes at least one first directional antenna sub-array, said first directional antenna sub-array including a first number of directional antenna elements. At least one of the plurality of directional antenna arrays includes at least one second directional antenna sub-array, said second directional antenna sub-array including a second number of directional antenna elements. The first number is different than the second number.

A semiconductor device capable of communicating with a host apparatus includes a symbol generation unit, a coding unit, and a transmission unit. The symbol generation unit includes a random number generation circuit and generates a symbol according to a random number generated by the random number generation circuit. The coding unit performs 8b/10b coding for the symbol. The transmission unit transmits the symbol coded by the 8b/10b coding unit to the host apparatus.

Apparatus and methods related to multipath bandpass filters with passband notches are provided herein. In certain configurations, a multipath bandpass filter includes multiple filter circuit branches or paths that are electrically connected in parallel with one another between an input terminal and an output terminal. The input terminal receives an input signal, and each filter circuit branch includes a downconverter that downconverts the input signal to generate a downconverted signal, a filter network that generates a filtered signal by filtering the downconverted signal, and an upconverter that upconverts the filtered signal to generate a branch output signal. The filter network includes at least one low pass filter and at least one notch filter to provide a passband with in-band notches. The branch output signals from the filter circuit branches are combined to generate an output signal at the output terminal.

The disclosed systems and methods are directed to transmitting and receiving symbols. In particular, splitting, a symbol dataset into symbol subsets, modulating, the symbol subsets using different sub-carriers, roll off factors and time acceleration factors, performing frequency shifting and combining the frequency shifted and modulated symbol subsets to generate a digital multiband (DMB) signal, transmitting and receiving the DMB signal, down converting the received DMB signal into a plurality of baseband signals, segregating the plurality of baseband signals in accordance with a manner by which the symbol subsets have been processed before transmission, forwarding a first portion of the plurality of baseband signals to a minimum mean square error (MMSE) based receiver, forwarding a second portion of the plurality of baseband signals to a matched filter-based receiver, and combining the output of the MMSE based receiver and matched filter-based receiver to generate an equivalent symbol dataset.