Lucent Technologies Inc.

Walter Joseph Kaminski

Arild T Kolsrud

Julio Antonio Garceran

A digital transmitter converts a digital signal into analog form with a digital to analog converter (DAC) and uses an analog signal image produced from the DAC to provide an analog signal at a transmission frequency and/or uses a projected analog signal image to produce analog signals for transmission. Rather than removing analog signal images with a low pass filter at the output of the DAC and/or using analog signal images and analog mixers for frequency conversion, the digital transmitter uses the analog signal images from the DAC to produce the analog signals at the desired frequency/frequencies. By setting and/or adjusting the conversion rate for the DAC and/or the digital signal frequency/frequencies, the analog signal images produced from the DAC can be positioned in the desired frequency band(s). For example, the digital transmitter can position the digital signals within non-overlapping portions of a conversion bandwidth defined as one-half the conversion rate for the DAC. When the digital signals are converted into analog form, the DAC produces analog signal images periodically repeated at multiples of one-half the conversion rate such that analog signal images are produced at the appropriate frequency band(s) for amplification and transmission.

Digital transmitter system and method

A receiver receives analog signals at radio frequency (RF), and the RF analog signals are converted into the digital domain. As such, the receiver does not require frequency conversion stage(s) prior to analog to digital conversion. For example, the receiver can comprise at least one antenna(s) which receives radio frequency (RF) analog signals at different frequency bands. The analog RF signals are provided to a single analog to digital (A/D) converter, and the A/D converter converts the analog RF signals at the different frequency bands into digital signals within the Nyquist bandwidth. By properly selecting the sampling rate of the A/D converter for the RF analog signals, the A/D converter can produce replicas of the different frequency bands of the analog signals in non-overlapping portions of the Nyquist bandwidth.

Receiver system using analog to digital conversion at radio frequency and method

A receiver provides received analog signals to a plurality of channel branches, and on at least one of the channel branches, the frequency of the received analog signals is adjusted independent of the relative positions of the corresponding analog signals in the radio frequency (RF) spectrum. The analog signals on the channel branches are then combined, and the combined analog signals are converted into the digital domain. For example, the receiver comprises at least one antenna(s) which receives radio frequency (RF) analog signals. A channel branch arranger receives the analog RF signals from the antenna(s) and provides the RF analog signals to a plurality of channel branches. A frequency conversion arrangement comprising at least one frequency converter on at least a respective one of the channel branches adjusts the frequency band of the analog RF signals on the respective channel branch independent of the relative positions of the corresponding analog signals in the RF spectrum of the different channel branches. The analog signals on the channel branches are combined, and a single analog to digital converter converts the combined analog signals into digital signals. In converting the composite analog signals into the digital domain, the frequency bands of the analog signals are positioned in a plurality of Nyquist zone channels in the digital domain. By properly selecting the frequency bands for the analog signals on the channel branches and the sampling rate for the A/D converter, the available bandwidth for the A/D converter can be more efficiently used, and/or time coherence and/or phase coherence can be provided.

Multiple branch receiver system and method

Piezoelectric crystals are arranged to function as variable resonators. In one embodiment, three crystals are arranged as an array, with a center crystal between two outer crystals. An electrical excitation of the outer crystals causes a mechanical displacement in the crystals along a common axis. This displacement squeezes the center crystal, resulting in a shift of the crystal's resonant frequency. By this arrangement, signals input to the outer crystals vary the resonant properties of the inner crystal.

Piezoelectric array devices

An array antenna for direction-finding includes antenna elements which define a triangular outline well-suited for meeting space constraints or reducing reflections from mounting conditions associated with the array antenna. The actual geometric configuration of the antenna elements is limited to certain triangular configurations with corresponding geometric correction factors to maintain the accuracy of estimating the angle of arrival. A processing system determines the appropriate angle of arrival based upon differential phases received in the antenna elements and the appropriate geometric correction factor.

Antenna system and method for direction finding

A filter including an enclosure, a dielectric material within the enclosure, at least two microstrip antennas within the enclosure, and at least one frequency selective surface including a metallic pattern. The frequency selective surface is utilized to filter an electromagnetic signal propagated within the enclosure. The geometry of the antennas and the frequency selective surfaces as well as the resonant frequencies of the frequency selective surfaces determine whether the filter is a bandpass, bandstop, notched, or combination filter. If the frequency selective surface is omitted, the combination acts as a delay circuit for delaying the electromagnetic signal, where the time delay is a function of the dielectric constant of the dielectric material.

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Long Valley, NJ, United States of America

Walter Joseph Kaminski