A system and method for communicating information signals using spread spectrum communication techniques. PN sequences are constructed that provide orthogonality between the users so that mutual interference will be reduced, allowing higher capacity and better link performance. With orthogonal PN codes, the cross-correlation is zero over a predetermined time interval, resulting in no interference between the orthogonal codes, provided only that the code time frames are time aligned with each other. In an exemplary embodiment, signals are communicated between a cell-site and mobile units using direct sequence spread spectrum communication signals. In the cell-to-mobile link, pilot, sync, paging and voice channels are defined. Information communicated on the cell-to-mobile link channels are, in general, encoded, interleaved, bi-phase shift key (BPSK) modulated with orthogonal covering of each BPSK symbol along with quadrature phase shift key (QPSK) spreading of the covered symbols. In the mobile-to-cell link, access and voice channels are defined. Information communicated on the mobile-to-cell link channels are, in general, encoded, interleaved, orthogonal signaling along with QPSK spreading.

System and method for generating signal waveforms in a CDMA cellular telephone system

An apparatus and method generate a linearly modulated signal in a polar modulation system. A signal for transmission is separated into a phase component and an amplitude component, and a carrier signal is modulated with the phase component in a phase modulator, creating a phase distortion. A compensator compensates for the phase distortion created by the phase modulator by modifying the amplitude component. The phase modulated carrier signal is amplitude modulated by the compensated amplitude component to produce a linearly modulated signal.

Method and apparatus for generating a linearly modulated signal using polar modulation

A peak power regulator is disclosed that functions within a Code Division Multiple Access (CDMA) transmitter to reduce peak power spikes within baseband signals, controlling the out-of-band emissions, and maintaining the in-band signal quality within an acceptable degradation. In-phase and quadrature baseband signals are input to an envelope magnitude predictor within the peak power regulator. The envelope magnitude predictor outputs an estimate for the magnitude of the envelope that will be generated when the inputted baseband signals are modulated. This estimate is input to a multiplier that generates a ratio by dividing the estimate by a maximum acceptable envelope magnitude. The ratio is subsequently input to a mapping table that outputs a scaling factor sufficient for reducing peak power spikes. The scaling factor is subsequently substracted from a value of one and multiplied by first delayed versions of the in-phase and quadrature baseband input signals. The outputs from these multiplication operations, after being filtered within lowpass filters to remove out-of-band emissions caused by the operations, are referred to as excess power correction signals. These excess power correction signals are then substracted from second delayed versions of the in-phase and quadrature baseband input signals to generate in-phase and quadrature baseband output signals.

Peak power and envelope magnitude regulators and cdma transmitters featuring such regulators

Several feed-forward RF power amplifiers configured for use in a distributed array, each having a main amplifier within a carrier null loop and an error amplifier within an error loop. Each carrier null loop includes a switch configured to selectively disable the carrier null loop, thereby disabling the carrier null loop, and injecting an actual RF signal into the error loop allowing the error loop to be optimized using the actual RF signal.

Optimization of error loops in distributed power amplifiers

A linear power amplifier and method for removing the intermodulation distortion with a predistortion system and a feed forward system. The linear power amplifier having a main power amplifier includes: a predistortion system for firstly suppressing the intermodulation signal generated upon amplification of an RF signal in the main power amplifier, by generating a harmonics corresponding to the input RF signal and a predistortion signal with coupling the RF signal to the harmonics; and a feed forward system for secondly suppressing the intermodulation signal by canceling the input RF signal and the output of the main power amplifier, extracting an intermodulation signal distortion, error-amplifying the extracted intermodulation signal distortion, and coupling the amplified intermodulation signal with the output of the main power amplifier.

Linear power amplifier and method for removing intermodulation distortion with predistortion system and feed forward system

A feed forward amplifier network (100) employs a method (300) and apparatus for reducing distortion contained in an output signal (142) of an amplifier circuit (101). A modulator (118, 120) modulates (303) an input signal (141) of the amplifier circuit (101) with a reference modulation. The amplifier circuit (101) amplifies (305) the modulated signal, introducing nonlinear distortion in the process. A modulation determination circuit (107, 109, 115) determines (307) the reference modulation in the amplified signal and provides the determined modulation to an adjustment circuit (105). The adjustment circuit (131,133, 135) adjusts (309) a characteristic of the determined modulation in response to a control signal (153,155) and combines (137, 311) the adjusted modulation with the amplified signal (142) at the output of the amplifier circuit (101) to produce a corrected signal (151). A residual modulation detection circuit (139, 125, 127, 129) demodulates (313) the corrected signal (151) to recover any residual modulation remaining in the corrected signal (151) and adjusts (317) the control signal (153, 155) to reduce the recovered residual modulation.

Method and apparatus for reducing distortion in an output signal of an amplifier

A simulcast broadcast uses digital signal processing techniques to scale pulse coded modulation samples of a signal for broadcast. Samples are adjusted to fully utilize all quantization levels representable by an 8-bit word. Time delay is adjustable using digital techniques by writing and reading data into and out of a RAM. Signal amplitude is adjustable by multiplying samples by a numeric factor. A computer can be used to adjust processing, delay and amplification of the digital signal processor.

Simulcast system and channel unit

A method and apparatus is provided for controlling a peak envelope power level in a power amplifier (PA) (10). The method includes the steps of measuring (101) a first peak envelope power value of an input of the PA during a first time period, comparing (102) the first peak envelope power value with a threshold value, and introducing a phase change (103) into a selected signal of a plurality of signals being amplified by the PA when the first peak envelope power value exceeds the threshold. The method further includes measuring (104) a second peak envelope power value during a second time period, comparing (105) the first and second peak envelope power values, and reversing (106) the phase change to the selected signal when the second peak envelope power value exceeds the first peak envelope power value.

Method and apparatus for controlling a peak envelope power of a pa

A method and apparatus for filtering interference signals to and from a broadband over power line system. The apparatus includes fixed notch filters and adaptive notch filters that filter interference signals that are generated and received by the system. The fixed filters are used for known interference signals, and the adaptive notch filters are used to filter unknown interference signals that are detected over time. The notch filters are configured at both a bridge and client of the system that send and receive broadband signals.

Method and apparatus for filtering of interference signals

The preliminary design phase of a ship acquisition program offers an overwhelming number of possible design configurations of which only a small number can be thoroughly developed by an experienced design team. This creates serious program risks, particularly when designing a ship that is fundamentally different from prior ships, such as an unmanned vessel. Set-based design offers a solution to this problem by separating functional disciplines into discrete sets that can be efficiently analyzed in parallel with one another. However, this process is still typically performed by teams of subject matter experts (SMEs) who are expensive to utilize and are potentially biased by past experiences or conventional thought patterns. The Serco Maritime Engineering Operations team has developed a new suite of software tools which attempts to improve upon a set-based design process by automating the generation of design points within each functional set. This software may be utilized in the first stage of any ship design program to provide the design team a high-level overview of the available design space by generating a large quantity of design seeds which can then be used as starting points for SMEs to develop ship concepts using conventional means for detailed trade studies and exploration.

John Ernest Matz

Papers

Method and apparatus for reducing distortion in an output signal of an amplifier

Simulcast system and channel unit

Method and apparatus for controlling a peak envelope power of a pa

Method and apparatus for filtering of interference signals

Software-Enabled Set-Based Ship Concept Design