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7096443 |
Method for determining the critical path of an integrated circuit
A method of determining the critical path of a circuit includes first determining the paths, their mean path transit times and their path transit time fluctuations. Paths having similar statistical...
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7015597 |
Power regulator for power inverter
A power inverter includes a regulator circuit that controls real and reactive power output by the inverter. The regulator measures real and reactive output power by calculating x-phasor components...
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6985824 |
Frequency measuring device
A frequency measuring device can measure the frequency of a noisy power system at high speed. The system voltage is measured at timings obtained by equally dividing one reference-wave period....
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6919727 |
Accurate time measurement system circuit and method
Disclosed is a method of measuring the time signal of an electronic device including steps for measuring a true signal and an inverted signal. The measured true path signal and inverted path signal...
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6759838 |
Phase-locked loop with dual-mode phase/frequency detection
A phase-locked loop with dual-mode phase/frequency detection is provided. The phase-locked loop circuit includes a dual-mode phase/frequency detector, a loop filter, a voltage-controlled...
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6737852 |
Clock skew measuring apparatus and method
A clock skew measuring apparatus for measuring a clock skew between a plurality of clock signals to be measured in a device under test, includes: a clock signal selecting element for receiving...
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6008663 |
Eliminating phase shift in an integrated circuit tester
An integrated circuit (IC) testing apparatus automatically detects and eliminates a phase difference between signals. A signal selection circuit 30 selects two test signals from a test pattern...
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5710710 |
Frequency counter with reduced false correlations
An improved frequency counter for more reliably reading the frequency of low level signals by employing a method of separating the desired signal from undesirable noise related signals, wherein the...
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5703489 |
Timing calibration circuit and method for test signals
A timing calibration circuit includes a plurality of variable delay circuits each of which is assigned to one of test signal paths to regulate a phase delay time for a signal passing therethrough,...
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5539655 |
Apparatus for detecting out of phase of power systems and method for detecting the same
An out of phase detecting apparatus according to the present invention includes a measurement unit for measuring an effective power and a current effective value at a tie point of power systems at...
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5471402 |
Frequency counter
An improved frequency counter for detecting and distinguishing a main input signal from amplifier generated self-oscillating signals, wherein the frequency counter generally includes an input...
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5452320 |
Method for detecting fine frequency deviation
A method for detecting a fine frequency deviation generated in a transmission line such as a general public telephone switching network. The method includes the steps of transmitting test signals...
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4843328 |
Apparatus for using a time interval counter to measure frequency stability
Apparatus for measuring the relative stability of two signals is disclosed comprising means for mixing the two signals down to a beat note sine wave and for producing a beat note square wave whose...
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4810947 |
Digital error detector for IFM receiver
A process and means for identifying erroneous frequency measurements made by an IFM receiver using a multi-channel delay line discriminator. Expected phase codes are compared with measured phase...
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4694263 |
Frequency modulation monitor circuit and method
A method and apparatus for monitoring a frequency modulated signal including harmonically mixing the modulated signal with a significantly lower reference frequency, dividing the mixed signal,...
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4672308 |
Enhanced frequency determination for spectrum analyzers or the like
An arrangement is provided for enhancing the accuracy of frequency determination in a spectrum analyzer or the like having a local oscillator heterodyned with and locked to a frequency comb, by...
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4661769 |
Measurement of magnitude and phase angle of voltage and current phasors and frequency deviation in power systems
Methods for determining magnitude, phase angle and frequency deviation in the sinusoid waveform output of electrical power generation equipment are disclosed. The first method uses a two-state...
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4636716 |
Device for testing units containing electrical circuits
For the purpose of testing units which contain electrical circuits, an interpretation circuit and a load circuit are connected to the output of the unit being tested by way of a line. A load...
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4628253 |
Clock signal test circuit
An integrated circuit which has serially connected clock drivers for generating sequential clock signals further includes test circuitry for testing for the occurence of the clock signals. The test...
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4547726 |
Means and method for measuring power system frequency
Samples from a first and second cycle of a system signal are used to generate discrete Fourier transforms for the respective first and second cycle. Multiplication of the discrete Fourier transform...
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4484291 |
Comparison circuit for determining the statistical equality of two analog signals
Signal comparison arrangement for comparing a first and a second analog signal with each other. For each of these signals the number of zero-crossings occurring within each measuring interval of a...
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4412299 |
Phase jitter detector
A phase jitter detector that is ideally suited for use in combination with tone receivers (e.g., tone-to-pulse converters) to provide a speech immune tone detection system or in a measuring...
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4405897 |
Frequency deviation testing and adjusting system for frequency modulated oscillators
Deviation of a frequency modulated oscillator (FMO) is set by applying a square wave test signal to the input of the oscillator so as to generate a predetermined amount of symmetrical periodic...
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4399408 |
Apparatus for testing the linearity of a frequency modulated oscillator
An APC (automatic phase control) circuit is utilized to measure the linearity of an FMO (frequency modulated oscillator). In accordance with a common APC concept a programmable divider is connected...
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4399409 |
Apparatus for testing the linearity of a frequency modulated oscillator
A linearity test signal generator alternately provides a burst of a modulation frequency and no modulation to the modulation input of the frequency modulator oscillator (FMO) under test. A...
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4370650 |
Tone detection circuitry
Tone detection circuitry including tone decoder providing a free running frequency determined by timing resistance and timing capacitance connected to it. A control means including a programmable...
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4350950 |
Frequency measuring method and apparatus
The frequency of a pulse signal is measured with the aid of a reference signal generated in an oscillator (11). Both the pulses of the frequency to be measured and the pulses of the reference...
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4319329 |
Frequency measuring and monitoring apparatus, methods and systems
Waveform frequency measuring apparatus and methods utilizing zero-crossing triggered analog-to-digital conversion apparatus combined with Discrete Fourier Transform (DFT) digital computing...
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4317223 |
RF Generator monitor circuit
An RF generator monitor circuit is provided for checking for variation in frequency of an RF generator outside predetermined limits. The circuit includes means for sampling the output of an RF...
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4313212 |
Electrical circuit arrangements, for example for use with communications receivers
A fully digitally-controlled system is disclosed which employs synthesized communications receivers to measure received signal frequency with greater resolution than that provided by the receiver...
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4303979 |
Frequency spectrum variation monitoring system
In a frequency spectrum variation monitoring system, the values of two parameters including the root mean square (RMS) value of each of the output signals from various detectors disposed at several...
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4258436 |
Multichannel RF signal generator
A device for generating a plurality of RF signals, all possessing identical odulation characteristics. A clock source triggers an oscillator to produce a precise pulse train that is filtered and...
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4254505 |
Normalization method and apparatus used when quantitatively measuring the reception quality of a received frequency-modulated ultrashort-wave signal
A frequency-modulated ultrashort-wave signal is received, but due to wave-reflection phenomena from physical bodies reflecting towards the receiving antenna is amplitude modulated, this amplitude...
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4249257 |
Radio frequency signals analyzer
An analyzer for analyzing radio frequency signals from an FM/PM transmitter ithout prior knowledge of the transmitting frequency. The RF signal is sampled and fed to a mixer where it is mixed with...
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4236110 |
Digital frequency deviation meter
A digital frequency deviation meter for measuring the deviation of an FM signal from a center frequency is disclosed. An incoming FM signal is applied to a counter which is cycled through a series...
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4216429 |
Method and apparatus for quantitatively measuring the reception quality of a received frequency-modulated ultrashort-wave signal
A frequency-modulated ultrashort-wave signal is received, but due to wave-reflection phenomena from physical bodies reflecting towards the receiving antenna is amplitude modulated, this amplitude...
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4207791 |
Automatic tuning device
An automatic tuning device for use in a synthesizer of an electronic musical instrument in which an error signal is produced corresponding to an output tone signal from each of a plurality of...
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4146836 |
Power monitor
A signal monitoring device useful to monitor power consumption level employs a phase locked loop and an associated frequency reduction circuit to convert relatively low frequency input pulse...
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4137496 |
Line frequency deviation monitor
A monitor for indicating deviation of an alternating current power source from a nominal operating frequency. The monitor circuit provides an indication when the frequency being measured is at its...
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4123704 |
Frequency deviation digital display circuit
A circuit is provided for monitoring a signal generated by an oscillator and producing a digital display of the sign and magnitude of the deviation of the actual frequency of the...
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4122391 |
Frequency deviation measuring and adjusting system
A calibrated unipolar signal is used to deviate a frequency modulator by a predetermined amount Δf from a carrier f 2 . An automatic frequency control circuit operates to bring the carrier back on...
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4121211 |
Method and apparatus for determining a signal of uniform period
The periods of several successive cycles of an alternating signal are determined and used to calculate the value corresponding to the statistical variance thereof. The deviation value is compared...
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4106280 |
Method and apparatus for synchronizing a mechanical oscillating system to the accuracy of a quartz standard
An arrangement for synchronizing a mechanical oscillating system to the accuracy of a quartz standard, in particular the timing of a clock. Timing pulses are derived from a quartz oscillation, and...
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4090126 |
Frequency marker generator
A frequency marker generator for providing marker pulses corresponding to known frequencies over a wide band of frequencies is disclosed. A signal having a predetermined frequency or known...
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4059804 |
Frequency comparison circuit
A frequency comparison circuit for determining, at least within certain limits of accuracy, whether the frequency of a received signal is equal or not to a frequency F. Generating means produce...
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4031464 |
Line power distortion detector
Apparatus for testing distortion of an AC power wave and providing an error signal if distortion of the type likely to cause DC output of a power supply receiving the AC power wave to fall below...
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4001680 |
Device for measuring small frequency differencies
A device for measuring small frequency differencies includes a phase detector followed by a differentiating circuit. In order to linearize the output from the differentiating circuit the time...
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4001695 |
Automatic deviation analysis meter
A system for automatically measuring frequency deviation without manual tuning or frequency selection includes a transfer oscillator circuit which is switchable between fast and slow loop response...
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3993984 |
Electronic underfrequency relay
A method and apparatus for detecting an underfrequency condition of an alternating current power line is disclosed wherein the frequency of the power line is sensed, an underfrequency signal is...
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3895293 |
Method and system for furnishing an indication of the deviation of the actual frequency of a low frequency signal from a nominal frequency
A high-frequency oscillator furnishes a high-frequency signal which is applied to the counting inputs of two counters each of which counts by frequency division. The pulse sequence derived from a...
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