Use of phase-locked-loop control for driving ultrasonic transducers
Phase-locked loop used as frequency control system for ultrasonic transducer
ULTRASONIC WAVE TRANSDUCER↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Vehicle tracking receiver design
Phase-locked loops and signal processing techniques employed in vehicle tracking receiver
PHASE LOCK↗
Special AROD System Studies, Volume I Fifth Quarterly Report, Period Ending Dec. 31, 1964
Wideband modulation techniques and phase-locked loop studies for airborne range and orbit determination system
PHASE LOCK↗
Stabilized gas laser oscillators Final report, 24 Jun. 1964 - 21 Jun. 1966
Phase-locking scheme for frequency-stabilized gas laser oscillators
PHASE LOCK↗
Spacecraft telemetry and command
Probability distribution of time to first loss of lock investigated by second order phase-locked loop - spacecraft telemetry and command
PHASE LOCK↗
Intermodulation distortion of a phase locked loop demodulator.
Intermodulation distortion of phase-locked loop demodulator as influenced by system parameters
PHASE LOCK DEMODULATOR↗
Wide-band doubler and sine wave quadrature generator
Phase-locked loop with photoresistive control, which provides both sine and cosine outputs for subcarrier demodulation, serves as a telemetry demodulator signal conditioner with a second harmonic signal for synchronization with the locally generated code.
Crow, R. B.↗
Design for a Rapid Automatic Sync Acquisition System
System provides rapid command sync acquisition between widely separated transmitter-receivers. It is based on a rapid, automatic range-adjustment approach rather than the time-consuming cycle slipping or stepping techniques of conventional phase-locked loops.
Anderson, T. O.↗
Radio frequency baseband recording technique
Technique uses a helical-scan video recorder with auxiliary signal-conditioning equipment to provide an inexpensive, high-capacity magnetic tape recording of a 112 channel, phase-locked, multiplexed, baseband signal.
Heckman, D. C.↗
Block-coded communications
Theory for block-coded telemetry systems is useful in testing performance of one- and two-way, phase-coherent telemetry systems when double-conversion, superheterodyne, phase-locked receiver, preceded by bandpass limiter is used to track carrier.
Lindsey, W. C.↗
Wide-range tracking oscillator generates phase and frequency coherent output
Tracking oscillator consists of modified phase-lock loop which controls voltage-controlled oscillator capable of automatic lock-on and track of periodic input waveform over frequency ratio 500-1. It is used in telemetry and communications systems where large signal fluctuations are encountered.
Howard, J. R.↗
Spectral analysis of oscillation instabilities in frequency standards
Phase and frequency fluctuations, inherent in oscillators used as frequency standards, are measured over spectral frequency range of 1 Hz to 5 kHz. Basic measurement system consists of electromechanical phase-locked loop that extracts phase and frequency fluctuations and error multiplier that extends threshold sensitivity.
Lippincott, S.↗
Study of applications of retrodirective and self-adaptive electromagnetic wave phase controls to a Mars probe, part 2 Final report, 26 Jan. - 31 Dec. 1967
Phase-locked loop operation in multipath environment and multipath effect on detection for Mars probe
Bershad, N. J.↗
Multipath error in range rate measurement by PLL-transponder/GRARR/TDRS
Range rate errors due to specular and diffuse multipath are calculated for a tracking and data relay satellite (TDRS) using an S band Goddard range and range rate (GRARR) system modified with a phase-locked loop transponder. Carrier signal processing in the coherent turn-around transponder and the GRARR reciever is taken into account. The root-mean-square (rms) range rate error was computed for the GRARR Doppler extractor and N-cycle count range rate measurement. Curves of worst-case range rate error are presented as a function of grazing angle at the reflection point. At very low grazing angles specular scattering predominates over diffuse scattering as expected, whereas for grazing angles greater than approximately 15 deg, the diffuse multipath predominates. The range rate errors at different low orbit altutudes peaked between 5 and 10 deg grazing angles.
Sohn, S. J.↗
An all digital phase locked loop for FM demodulation.
A phase-locked loop designed with all-digital circuitry which avoids certain problems, and a digital voltage controlled oscillator algorithm are described. The system operates synchronously and performs all required digital calculations within one sampling period, thereby performing as a real-time special-purpose computer. The SNR ratio is computed for frequency offsets and sinusoidal modulation, and experimental results verify the theoretical calculations.
Greco, J.↗
Synthesis and evaluation of phase detectors for active bit synchronizers
Self-synchronizing digital data communication systems usually use active or phase-locked loop (PLL) bit synchronizers. The three main elements of PLL synchronizers are the phase detector, loop filter, and the voltage controlled oscillator. Of these three elements, phase detector synthesis is the main source of difficulty, particularly when the received signals are demodulated square-wave signals. A phase detector synthesis technique is reviewed that provides a physically realizable design for bit synchronizer phase detectors. The development is based upon nonlinear recursive estimation methods. The phase detector portion of the algorithm is isolated and analyzed.
Mcbride, A. L.↗
Clock synchronization of a large multiprocessor system in the presence of malicious faults
An interconnection algorithm is presented for achieving clock synchronization in a multiprocessor system. The system is assumed to be maliciously faulty, i.e., some processors are out of synchronization and lie about their clock state to other intragroup or intergroup processors. A phase-locked clock network design is proposed which groups the clocks in the system into diverse clusters. The clusters are then treated as single clock units from the perspective of the network. The algorithm minimizes the number of interconnections while permitting synchronization of large multiprocessor systems controlling time-critical applications such as aircraft, nuclear reactors and industrial processes.
Shin, Kang G.↗
Design Concept for a Rapid Automatic Sync Acquisition System
A design has been conceived for a system intended to provide rapid command sync acquisition between widely separated transmitter-receivers, such as between a spacecraft telemetry transmitter, and a ground-based receiver. Use of the system in commercial satellite communications would facilitate rapid sync acquisition between stations and regaining of data lock after interruption or equipment failure. The system is based on a rapid, automatic range-adjustment approach rather than the time-consuming cycle slipping or stepping techniques of conventional phase-locked loops.
Anderson, T. O.↗