Showing papers on "Phase noise published in 1970"
TL;DR: An electronic neural analog is described which contains variable absolute and relative refractory periods, two time constants, and separate control of the ``accommodation'' to sub-threshold voltage changes and the ``adaptation'' produced by the occurrence of output pulses (spikes).
Abstract: An electronic neural analog is described which contains variable absolute and relative refractory periods, two time constants, and separate control of the ``accommodation'' to sub-threshold voltage changes and the ``adaptation'' produced by the occurrence of output pulses (spikes). The extensive use of integrated-circuit operational amplifiers permits an accurate description of input-output relationships over a wide range of values for all parameters. This facilitates comparison of the results obtained both with neural data and mathematical or digitally simulated models of neural activity. The effect of white noise on interval histograms and their parameters is described and its effect when added to other inputs. Noise disrupts the phase-locked patterns produced by sinusoidal stimuli and the averaged response may become a smooth sinusoidal function in the presence of added noise. Adaptation may produce a phase lead to sinusoidal stimuli, while accommodation may produce a phase lag. Corresponding overshoots or undershoots are seen with square-wave inputs.
99 citations
TL;DR: The effect of noise on the modulation transfer function was studied by means of threshold measurements and an attempt was made to explain the results by visual observation of the bar pattern in the presence of narrow-bandwidth noise.
Abstract: The effect of noise on the modulation transfer function was studied by means of threshold measurements. White noise and 1/f noise of various levels and different cutoff frequencies were displayed on a television screen together with a sinusoidally modulated bar pattern. The signal-to-noise threshold necessary for perception was measured as a function of the spatial frequency of the bar pattern. This signal-to-noise threshold, in addition to being strongly dependent on the bar-pattern frequency is also dependent on the rms value and the frequency distribution of the noise as well as the difference between the bar-pattern frequency and medium frequency of the noise. An attempt was made to explain the results by visual observation of the bar pattern in the presence of narrow-bandwidth noise.
38 citations
TL;DR: The steady-state phase noise performance of an absolute value type of early-late gate bit synchronizer is developed using the Fokker-Planck method and yields the best performance (in the sense of minimum phase noise) at every value of R s.
Abstract: The steady-state phase noise performance of an absolute value type of early-late gate bit synchronizer is developed using the Fokker-Planck method. The results are compared with the performance of two other commonly used bit synchronizer circuit topologies on the basis of either 1) equal equivalent signal to noise in the loop bandwidth in the linear region, or 2) equal loop bandwidth at each input signal-to-noise ratio R s . These comparisons are made as a function of R s . In both cases, the absolute value type of early-late gate yields the best performance (in the sense of minimum phase noise) at every value of R s .
36 citations
Patent•
28 Oct 1970TL;DR: In this article, an auxiliary injection phase-locked oscillator is used to provide a signal of sufficient level for operation of a high-frequency discriminator used for noise measurement, and the auxiliary oscillator may additionally be used for calibration of the discriminator preliminary to taking noise measurements.
Abstract: Apparatus is provided for the measurement of frequency modulation noise on the carrier signal output of a low-noise, low-power, high-frequency diode oscillator under test. An auxiliary injection phase-locked oscillator, driven by the oscillator under test, is used to provide a signal of sufficient level for operation of a high-frequency discriminator used for noise measurement. The auxiliary oscillator may additionally be used for calibration of the discriminator preliminary to taking noise measurements.
32 citations
TL;DR: The steady-state behavior of a data-transition tracking loop, used as a bit synchronizer in a phase-coherent receiver, is considered and it is shown that by adjusting the quadrature channel gain along with the integration interval, a significant improvement in phase noise and cycle slip performances can be achieved.
Abstract: The steady-state behavior of a data-transition tracking loop, used as a bit synchronizer in a phase-coherent receiver, is considered. Optimization of mean-square phase noise and mean time to first cycle slip is performed when the average power of the reference cross-correlating signal is constrained. It is shown that by adjusting the quadrature channel gain along with the integration interval, a significant improvement in phase noise and cycle slip performances can be achieved over that system which integrates in the quadrature channel over the full symbol period. All the results are derived for a first-order loop filter merely to indicate the approach to the problem and the relative value of optimizing the system.
23 citations
TL;DR: In this paper, the bit error probability performance of both frequency-shift-keyed (FSK) and differential phase-shift keyed (DPSK) binary systems are described when disturbed by an interference consisting of a mixture continuous wave (CW) tone and narrow-band random noise in addition to the usual broad-band thermal noise background.
Abstract: The bit error probability performance of both frequency-shift-keyed (FSK) and differential phase-shift-keyed (DPSK) binary systems are described when disturbed by an interference consisting of a mixture continuous wave (CW) tone and narrow-band random noise in addition to the usual broad-band thermal noise background. Performance of the two systems is shown to be identical with the exception that the equivalent DPSK performance occurs at 3 dB less signal-to-thermal-noise ratio. The combination of CW tone and noise interference severely degrades system performance under a broad range of conditions.
14 citations
01 Jan 1970
TL;DR: In this article, a 9.72 GHz avalanche transit time oscillator (ATTO) with FM noise of 100 Hz rms/100 Hz was synchronized by a stabilized klystron with 0.01 Hz rm/100 kHz.
Abstract: A 9.72 GHz avalanche transit time oscillator (ATTO) with FM noise of 100 Hz rms/100 Hz was synchronized by a 9.72 GHz stabilized klystron with FM noise of 0.01 Hz rms/100 Hz. The FM noise of the synchronized oscillator was reduced, but not as much as expected for modulation frequencies below 10 kHz. The AM noise was not changed by synchronization.
12 citations
TL;DR: In this article, the first-order phase-locked loop in the presence of noise is investigated and numerical integration is used to obtain solutions for the Fokker-Planck equation which represents loop dynamics.
Abstract: Transient behavior of the first-order phase-locked loop in the presence of noise is investigated. Numerical integration is used to obtain solutions for the Fokker-Planck equation which represents loop dynamics, Results illustrate quantitative behavior of the time-varying probability density function of phase error when the input is a constant frequency sinusoid in the presence of additive white Gaussian noise. Several selected values of signal-to-noise ratio (SNR) are considered.
11 citations
01 May 1970
TL;DR: The FM noise spectrum of a Gunn oscillator is composed of two components: a white component which depends on loaded Q and carrier power, and a flicker component that depends on the oscillator's voltage pushing.
Abstract: Measurements indicate that the FM noise spectrum of a Gunn oscillator is comprised of two components. The first is a white component which depends on loaded Q and carrier power, and the second is a flicker component which depends on the oscillator's voltage pushing.
10 citations
TL;DR: In this paper, the spectral density of phase noise on carrier frequencies from 1 to 500 MHz, for offset frequencies from 20 Hz to 50 kHz, is measured using a test set with a residual single-sideband phase-noise-power-to-signal power ratio of -142 dB/Hz at 20 Hz offset from the carrier, which decreases to a floor of -172 dB /Hz at offset frequencies greater than 5 kHz.
Abstract: The test set described here is capable of measuring the spectral density of phase noise on carrier frequencies from 1 to 500 MHz, for offset frequencies from 20 Hz to 50 kHz. Measurements to 50 MHz are described. The test set has a residual single-sideband phase-noise-power-to-signal-power ratio of -142 dB/Hz at 20 Hz offset from the carrier, which decreases to a floor of -172 dB/Hz at offset frequencies greater than 5 kHz. The estimated calibration accuracy achievable is ±0.8 dB, exclusive of random reading errors due to the Gaussian distribution of the phase fluctuations being observed. The estimated 1 ? repeatability of a measurement is 0.7 dB (70 percent of the observations on a given test will fall within ±0.7 dB of the average value). This test set is capable of characterizing the phase-noise performance of existing atomic frequency standards, crystal oscillators, frequency synthesizers, and other high-quality sources more accurately than has previously been possible. The increased accuracy has been achieved by a system design that minimizes readout fluctuations, allows for the accurate measurement of correction factors used to reduce systematic errors, and minimizes the possibility of operator error and bias.
9 citations
TL;DR: In this article, an injection phase-locked oscillator is used as an input microwave-limiting amplifier for a microwave discriminator (FM demodulator) used for noise measurement.
Abstract: An injection phase-locked oscillator is used as an input microwave-limiting amplifier for a microwave discriminator (FM demodulator) used for noise measurement. This amplifier simultaneously increases sensitivity by 6 dB and reduces the threshold (minimum measurable FM) by at least 10 dB. The oscillator can be frequency-modulated to calibrate the measurement.
TL;DR: In this paper, a simple explanation on the operation and equation of phase motion of an injectionsynchronized oscillator in the presence of incoming noise in a simple way with particular reference to the effect of partly instantaneous limiting, due to the self-bias circuit of the oscillator.
Abstract: This correspondence presents a simple explanation on the operation and equation of phase motion of an injectionsynchronized oscillator in the presence of incoming noise in a simple way with particular reference to the effect of partly instantaneous limiting, due to the self-bias circuit of the oscillator. A simple relation between the mean-square frequency error and the time constant of the self-bias circuit has also been found by the application of the Fokker-Planck technique.
TL;DR: A procedure for the design of nearly optimum unconditionally stable phase-lock demodulators is given in this article, where various noise contributions at threshold are investigated and procedures to reduce the noise due to losses of lock are discussed.
Abstract: A procedure for the design of nearly optimum unconditionally stable phase-lock (PL) demodulators is given The various noise contributions at threshold are investigated and procedures to reduce the noise due to losses of lock are discussed Experimental results of a nearly optimum 24-telephone-channel PL demodulator equipped with a particular type of threshold noise compensator are given
TL;DR: In this paper, the measured FM noise spectra of subharmonically phase-locked avalanche transit-time oscillators are presented and an improvement of the frequency-modulation noise is achieved.
Abstract: Measured FM noise spectra of subharmonically phase-locked avalanche transit-time oscillators are presented. An improvement of the frequency-modulation noise is achieved.
TL;DR: A technique is described for the removal of coherent noise from digitized signals by using cross correlation to identify the noise parameters.
Abstract: A technique is described for the removal of coherent noise from digitized signals by using cross correlation to identify the noise parameters The approach is particularly useful for removing power system noise from short digitized physiological signals (ECG, EEG)
TL;DR: In this paper, the locus of the load circuit orthogonal to the curve of the device impedance was adjusted to reduce the a.m. noise by a quasistationary method.
Abstract: Based on a general oscillator model, noise spectra are calculated by a quasistationary method. From this, the reduction of the a.m. noise caused by adjusting the locus of the load circuit orthogonal to the curve of the device impedance is indicated and verified by experiments. The noise reduction generally is 5?15 dB. Measurements of the a.m.-f.m.-noise-correlation coefficient confirm the results.
11 May 1970
TL;DR: In this paper, the authors showed that cavity stabilization of microwave oscillators can be characterized by a Type O (AFC) servomechanism, which can be used to analyze phase noise spectral density as a function of modulation rate.
Abstract: This paper shows cavity stabilization of microwave oscillators can be characterized by a Type O (AFC) servomechanism. Stabilized phase noise spectral density can now be analyzed as a function of modulation rate. Measured phase noise data of stabilized IMPATT and Gunn oscillators are compared with the new theory.
01 Jun 1970
TL;DR: In this article, the frequency instability of an oscillator whose internal thermal noise is its sole source of noise is defined by a standard expression [1, (16] tending to infinity when τ → 0, and hence unsuitable to cover very short-term instabilities.
Abstract: The frequency instability, over a period τ, of an oscillator whose internal thermal noise is its sole source of noise is defined by a standard expression [1, (16)] tending to infinity when τ → 0, and hence unsuitable to cover very-short-term instabilities. The present letter demonstrates a fuller expression applicable to any value of τ ≥ 0.
TL;DR: In this article, the impacts of chromatic dispersion in OD8PSK systems (Optical Differential 8-Level-Phase-Shift Keying), then a long-haul differential 8-level phase-shift keying (OD8PSk) transmission simulation is studied in order to compare both the performance of the dispersion compensating fiber (DCF) and the midspan optical phase conjugation.
Abstract: The problem of the phase noise generated by nonlinear effects and chromatic dispersion can limit the transmission distance and the bit rate for phase-shift-keying modulation formats. In this paper, the compensation of the nonlinear and linear effects by a midspan optical phase conjugation (OPC) is studied. First, we show the impacts of chromatic dispersion in an OD8PSK systems (Optical Differential 8-Level Phase-Shift Keying), then a long-haul differential 8-Level Phase-Shift Keying (OD8PSK) transmission simulation is studied in order to compare both the performance of the dispersion compensating fiber (DCF) and the midspan optical phase conjugation. OPC allow to obtain a best recovered of transmitted information especially when compared to a «conventional» transmission system; the latter uses dispersion compensating fiber (DCF). OPC performs better even if we increase the bit rate and the distance. Key words : alternative modulation formats; Optical Differential 8-Level Phase-Shift Keying (OD8PSK); dispersion compensation; fiber optics communications; nonlinear phase noise; optical phase conjugation; spectral inversion.
Patent•
07 Apr 1970TL;DR: In this paper, a high carrier-frequency semiconductor diode oscillator is frequency stabilized against variation in loading and amplitude modulation noise in its output by utilization of a limiter-diode of the PIN type in the output transmission line.
Abstract: A high carrier-frequency semiconductor diode oscillator is frequency stabilized against variation in loading and amplitude modulation noise in its output is reduced by utilization of a limiter-diode of the PIN type in its output transmission line.
TL;DR: If the loop parameters are defined appropriately, then the dynamic noise performance of the loop is identically equivalent to that of a standard phase-locked loop or a double-superheterodyne tracking loop using a noise-free external reference generator.
Abstract: A double-superheterodyne tracking loop using two frequency converters to provide coherent reference signals for demodulation is analyzed and compared to two other well-known configurations. It is shown that if the loop parameters are defined appropriately, then the dynamic noise performance of the loop is identically equivalent to that of a standard phase-locked loop or a double-superheterodyne tracking loop using a noise-free external reference generator.
Patent•
06 Nov 1970
TL;DR: In this article, the delta noise decay function is combined with a separately generated function derived from the decay function to cancel or reduce the amplitude in the decaying period to improve memory access time.
Abstract: Method and means for delta noise cancellation for memory systems in which the delta noise decay function is combined electronically with a separately generated function derived from the delta noise decay function to cancel or reduce the delta noise amplitude in the decaying period to improve memory access time.
TL;DR: In this article, the authors describe a system for the measurement of AM noise in amplifiers and oscillators pulsed on for durations on the order of a microsecond or less.
Abstract: The noise properties of amplifiers and oscillators are critical in systems applications. This paper describes a system for the measurement of AM noise in amplifiers and oscillators pulsed on for durations on the order of a microsecond or less. Such a system is useful in measuring AM noise in pulsed solid-state microwave devices such as avalanche- and Gunn-diode simplifiers and oscillators, where heat-dissipation limitations sometimes make continuous operation impossible.
10 Jul 1970
TL;DR: Aquisition time parameter for first order phase lock loop with sine wave input in additive Gaussian noise is given in this paper, where the sine-wave input is assumed to be constant.
Abstract: Aquisition time parameter for first order phase lock loop with sine wave input in additive Gaussian noise
01 Nov 1970
TL;DR: A fast method of measuring the power spectral density of transistor noise from dc to 10 kHz is described, based on digital analysis of sampled data, and applicable to a wide variety of noise measurements.
Abstract: A fast method of measuring the power spectral density of transistor noise from dc to 10 kHz is described. The method is based on digital analysis of sampled data, and is applicable to a wide variety of noise measurements.
TL;DR: In this article, the theory leading to optimum frequencies is shown, and equations for the direct calculation of the baseband-interference loading noise are given, and reference is made to experimental results.
Abstract: There exists a special kind of loading noise in highly linear push-pull frequency modulators used in radio links. It is caused by the higher order interference products in the mixer of the modulator. This noise can be very annoying and necessitates a careful selection of the oscillator frequencies. The theory leading to optimum frequencies is shown, and equations for the direct calculation of the baseband-interference loading noise are given. Reference is made to experimental results.
01 Jan 1970
TL;DR: In this article, a single-parameter tunable null network oscillator is presented and a theoretical frequency tuning range of zero to infinity is obtained for the parameter variation between unity and zero.
Abstract: SUMMARY A single-parameter tunable null network oscillator is presented. A theoretical frequency tuning range of zero to infinity is obtained for the parameter variation between unity and zero. The expression for frequency stability is derived and found to depend on the oscillator frequency. A practical version of the oscillator was found to give good frequency stability over a one-decade range.
01 Jan 1970
TL;DR: In this paper, the steady-state phase noise performance of an absolute value type of early-late gate bit synchronizer was investigated using the Fokker-Planck method. And the results were compared with the performance of two other commonly used bit synchronization topologies on the basis of either equal equivalent signal to noise in the loop bandwidth in the linear region, or equal loop bandwidth at each input signal-to-noise ratio R.
Abstract: The steady-state phase noise performance of an absolute value type of early-late gate bit synchronizer is developed using the Fokker-Planck method. The results are compared with the performance of two other commonly used bit synchronizer circuit topologies on the basis of either 1) equal equivalent signal to noise in the loop bandwidth in the linear region, or 2) equal loop bandwidth at each input signal-to-noise ratio R,. These com- parisons are made as a function of R,. In both cases, the absolute value type of early-late gate yields the best performance (in the sense of minimum phase noise) at every value of R,.
TL;DR: In this article, the measurement of low-frequency noise by the method of frequency-spectrum transformation (the magnetic-tape method) is at present not sufficiently acceptable, and analog RC filters and counting volt meters are the most promising methods of measurement.
Abstract: 1. The measurement of the noise of semiconductor instruments in the range of infrasonic frequencies is of great scientific and practical interest. 2. At present various methods and equipment have been developed for measuring the characteristics of noise at frequencies right down to 5·10−5 Hz. 3. The measurement of low-frequency noise by the method of frequency-spectrum transformation (the magnetic-tape method) is at present not sufficiently acceptable. 4. Comparative methods of measurement using analog RC filters and a counting voltmeter are the most promising; these methods can be used to measure noise in the frequency range from several hertz down to frequencies of the order of 10−5 Hz.