Abstract: The number of power amplifiers required to amplify a plurality of transmission signals is reduced by using non-linear transmission lines (NTL) circuits. In general, a “combining” NTL circuit is used to combine the plurality of transmission signals to form a soliton pulse. The soliton pulse is then amplified such that each of its component transmission signals are amplified. A “dividing” NTL circuit is then used to divide the amplified soliton pulse into its component amplified transmission signals. The amplified transmission signals can therefore be transmitted over a communications channel without requiring a separate power amplifier for each.

Abstract: Passive recognition tags are disclosed that function along with a transceiver and a processor in a system which identifies distant items. Each tag includes a SAW substrate on which sync and tap transducers are commonly connected between positive and negative buses across which an interrogating signal is applied through an antenna. In response to that signal, in phase identification code signals pass to the antenna from both the sync transducer and the tap transducers. Transducer spacing is minimized relative to acoustic reflection considerations by disposing the tap transducers in a plurality of channels which are aligned in parallel across the width of the substrate on both output sides of the sync transducer.

Abstract: A circuit is disclosed for detecting RF pulses, regardless of the frequens associated therewith. Such pulses are characterized by envelope configurations of a common frequency and perceived with a frequency analyzer that responds to that common frequency. In the preferred embodiments, a static Chirp-Z analyzer is incorporated when narrow pulses are of primary interest and a dynamic Chirp-Z analyzer is incorporated when wide pulses are of primary interest. In other embodiments, static transform gain is enhanced with dynamic transform gain.

Abstract: A SAW substrate is disclosed which can be adapted to a particular signal in multitude of signal possibilities. Each signal adaptation is made by connecting alternate electrodes of sequential tap transducers to either a positive bus or a negative bus, through auxiliary buses. A pair of the auxiliary buses is dedicated to each tap transducer, with one auxiliary bus in each pair being disposed adjacent to the positive bus and the other auxiliary bus in each pair being disposed adjacent to the negative bus. A pad is associated with each auxiliary bus for locating it adjacent to the positive bus or the negative bus which is not otherwise adjacent thereto. When a large number of signal possibilities are necessary, an unreasonably lengthy substrate is avoided by aligning the tap transducers in parallel channels across the substrate.

Abstract: A soliton rejection filter circuit is provided, for use in RF signal procing, for isolating a low level signal in the presence of stronger nearby interfering signals and detecting its modulation over a wide communication bandwidth centered at a relatively low RF frequency. The soliton filter circuit includes a nonlinear transmission line and a filter circuit.

Abstract: Discernible frequency characteristics regarding BPSK and CW signals are dved from consecutive transform outputs of a dual channel chirp-Z processor. Physically separated antennas direct the signals to the chirp-Z channels and concurrently occurring transforms are directed from those channels to a particular phase detector in accordance with the type of signal to which such transforms relate. The selection of phase detector is made through switches which are controlled by logic circuitry in accordance with the discernible frequency characteristics.

Abstract: Two wide dynamic range detection circuits are disclosed, which are capable of detecting low-level desired signals in the presence of nearby strong interfering signals. Each circuit includes an attenuator scheme for attenuating the interfering signal while passing the desired signal. The first attenuator scheme uses a YIG filter in combination with an automatic gate arrangement. The second attenuator scheme uses a two-channel arrangement. The first channel uses a chirp-Z processor to derive a pulse-type transform signal in response to the strong interference signal. The second channel includes a YIG filter followed by a programmable notch filter which is controlled by the interference-signal pulse from the first channel. Following the programmable notch filter in the second channel is a chirp-Z processor followed by a gate arrangement wherein the gates are switched "OFF" under control of the interference-signal pulse from the first channel.

Abstract: A circuit is disclosed for deriving a modified Chirp-Z transform that focs on a narrow bandwidth within a solitary time interval and thereby assures RF pulse detection with the characteristic gain of conventional Chirp-Z transforms. RF pulse detection bandwidth enhancement is accomplished with this circuit by arranging it in a plurality of parallel channels which each relate to one RF pulse frequency within that bandwidth.

Abstract: Use of inverse transforms regarding chirp-Z analysis is circumvented to ence the chirp-Z output gain. Forward chirp-Z transform pulses relating to individual CW frequency components of interest in a composite signal, are gated to circuitry which replicates those pulses to recreate each such component for the time necessary to accomplish the intended analysis. This circuitry operates at the replicating rate necessary to separate the pulse replications by one-half the width of the pulses.

Abstract: Stable feedback circuitry is disclosed for recreating selected CW components of a signal without distortion. Chirp-Z pulses relating to the CW component are continuously replicated at the rate necessary to separate the pulse replications by half the uniform Chirp-Z pulse duration.

Abstract: Disclosed is a real time interference signal rejection circuit which utils a conventional chirp-Z analyzer to generate a critical number and stop a counter circuit. The critical number is then read by a microprocessor which calculates new tap values from a set of predetermined tap values to reprogram a programmable filter.

Abstract: A sensor for chemical vapor detection using a surface acoustic wave (SAW) ray that provides a means for simultaneously detecting several chemical agents. The sensor has a piezoelectric substrate and a bidirectional surface acoustic wave transducer on the substrate. Also on the substrate are several pairs of identical acoustic sensing and reference channels each on opposite sides of the transducer in a mirror image fashion. Each channel pair has a thin film capable of absorbing a chemical vapor to be monitored and a metallic surface acoustic wave grating reflector capable of receiving and reflecting surface acoustic waves through the thin film and back to the transducer. An acoustic absorber separates each channel. The reference channels are protected from ambient conditions while the sensing channels are exposed to such conditions. An RF signal is applied to the transducer causing the propagation of an acoustic signal into each of the sensing channels and reference channels.

Abstract: This disclosure relates to a circuit for detecting the phase transitions in a PSK signal in the presence of a stronger CW signal. A SAW transform circuit carries out "piecewise" Chirp-Z transformations of the PSK and CW signals so as to achieve a separation of the same in the time domain. A gate and a pulse width discriminator are both coupled to the output of the Chirp-Z transform circuit. The discriminator rejects all signals except the transformed phase transitions of the PSK signal. The output of the discriminator is utilized to periodically enable the gate for short durations (e.g., 2nsec.) to selectively pass the transformed PSK signal including transformed phase transitions thereof. The gated output is delivered to a dual channel SAW differential delay line whose two channels are of different lengths to provide a predetermined amount of delay (t) therebetween (t.ltoreq.PSK bit duration).

Abstract: The disclosed system measures the phase relationship of first and second K signals received at a pair of receiving antennas. The antennas are connected to respective first and second converting circuits which convert the received signals into first and second CW signals. Each CW signal is subjected to chirp-Z processing so as to convert the first and second CW signals into first and second chirp-Z transforms, which are narrow pulses. Then, the phase relationship of the first and second narrow pulses is detected, so as to thereby detect the phase relationship of the first and second received BPSK signals. That phase information can be used, for example, to calculate the angle-of-arrival (AOA) of the received BPSK signals. Advantageously, each converting circuit includes a series connection of a frequency-doubling circuit, a bandpass filter, and a circuit for dividing frequency by two, in that order.

Abstract: Wide band and narrow band Chirp-Z channels are interfaced to enhance signal nalysis resolution for the signal's individual component wave forms over a wide signal bandwidth. The frequency characteristic of a selected component wave form is matched to the sweeping local oscillator and filter frequency parameters of the narrow band channel in accordance with the relative position occupied by the frequency characteristic of the selected component wave form in the frequency segregated time domain of said wide band channel. In one preferred embodiment, a mixer and a voltage controlled oscillator are utilized to accomplish the frequency matching and in another embodiment, a band-pass filter precisely defines the bandwidth of the selected component wave form. For still another embodiment, the voltage input to the voltage control oscillator is controlled in accordance with the difference in frequency between the selected component wave form and said narrow band channel.

Abstract: A real-time rejection circuit for passing low level desired signals in the resence of one or more strong, interfering signals. A chirp-Z transform system separates the various frequency components of a received signal into frequency segregated time domain signals. A power splitter separates the time domain signal into two paths. One path includes a modulator or switch that is normally biased "ON" for passing the time domain signal. The second path includes a diode detector that produces pulses of sufficient strength when a strong interfering component is present to override the bias and turn the modulator "OFF" for a sufficient period of time to attenuate the unwanted frequency components in the other path. The modulator output will primarily contain the low level desired frequency components that are passed through an inverse transform device for producing a frequency domain signal of the desired signal uncorrupted by unwanted signals.

Abstract: A SAW slanted array correlator (SAC) comprises a piezoelectric substrate, input and an output interdigital transducer deposited on the piezoelectric substrate, a reflective array aligned with the transducers, and an acoustic absorbing film disposed on the substrate between the output transducer and the reflective array. The input and output transducer are slanted at equal and opposite appropriate angles to each other. The reflective array is disposed on the substrate at an angle the same as the angle of emplacement of the output transducer. The transducers comprise a number of interdigital electrodes with varying periodicity, the periodicity being the same for corresponding portions of the two transducers. The reflective array comprises a number of shorted electrodes having a periodicity corresponding to the periodicity of the output transducer. The acoustic absorbing film has a non-uniform width with selected portions having little or no width.

Abstract: A SAW slanted array correlator (SAC) comprises a piezoelectric substrate, an input and an output interdigital transducer deposited on the piezoelectric substrate, and a reflective array aligned with the transducers. The input and output transducer are slanted at equal and opposite appropriate angles to each other. The reflective array is disposed on the substrate at an angle the same as the angle of emplacement of the output transducer. The transducers comprise a number of interdigital electrodes with varying periodicity, the periodicity being the same for corresponding portions of the two transducers. The reflective array comprises a number of shorted interdigital electrodes having a periodicity corresponding to the periodicity of the output transducer. The reflective array comprises portion of selected electrodes which are active, partially active or inactive.

Abstract: A phase transition detector for PSK signals which utilizes a dual channel SAW differential delay line to achieve a required delay. Each channel or path of the SAW device comprises an input and an output transducer. The two channels provide a predetermined differential delay (T) inasmuch as they are of different lengths. A PSK input signal is delivered to a power splitter, with the output therefrom coupled to the pair of input transducers of the SAW device. The output transducers are coupled to a multiplier which serves to detect phase transitions in the input PSK signal. The multiplier output is coupled to an output terminal via a low pass filter which provides harmonic repression. In another embodiment a SAW device comprises a bank of dual channel differential delay lines with each dual channel set to a different predetermined delay (T) so that a plurality of PSK signals of different chip rates can be separated out and detected.

Abstract: Phase shifted frequency components of wide bandwidth, composite signals are ocused for analysis with high resolution by circuitry which includes both a Chirp-Z and a superheterodyne signal analyzer. An interface between the analyzers synchronizes the outputs therefrom relative to each phase shifted frequency component. Preferred embodiments are disclosed with the analyzers generally arranged in either parallel or series and replicating circuitry may be included in the latter to sustain the integrity of the phase shifted frequency components for some predetermined period of time.