Matches 151 - 200 out of 230 < 1 2 3 4 5 >
Match Document Document Title
4309656 Level indicating circuit  
A level indicating circuit includes a pair of transistors, arranged as a differential amplifier and to whose bases an input signal is applied, a level-detecting circuit to supply to a meter or the...
4288748 Method for testing metal detectors  
An apparatus and method for testing low-power, low-band radio frequency metal detectors of the type employing a radio transmitter alone or a transmitter and a receiver. The apparatus is...
4247949 Signal strength detecting circuit  
An input signal is applied to a first limiting amplifier circuit, and an output of the first limiting amplifier circuit is applied to a second limiting amplifier circuit. An output of the second...
4241448 High sensitivity dual function meter circuit  
In a radio receiver or transmitter circuit, a high sensitivity dual function meter circuit for metering the DC and AC operation of a circuit stage is constructed by connecting a detector diode to a...
4234964 Radio receiver monitoring and testing apparatus  
Circuitry for attachment to a radio receiver to monitor and test a detected intermediate frequency signal and an audio signal from a demodulator portion of the receiver to determine whether a...
4232398 Radio receiver alignment indicator  
A predetermined frequency alignment signal and a white noise source signal are alternately switched through the intermediate frequency amplifier stage (IF) of the receiver being aligned. A series...
4227255 Signal classifier  
A signal classifier performs measurements on an IF signal and determines from these measurements the nature of the modulation, if any, appearing on a received high frequency communications signal....
4225969 Method and apparatus for testing a frequency synthesizer in an RF modem  
A multiple frequency RF modem includes a frequency synthesizer for providing local oscillator signals to double balanced mixer circuits in both the transmitter and receiver sections. To test the...
4201944 Receiver having a measurement instrument which is used as a tuning scale  
With a receiver, tunable by means of a tuning voltage, which receiver is provided with a measuring instrument as a tuning scale, a convenient adjustment of presetting potentiometers to transmitters...
4186351 Signal strength indicator circuit for a radio receiver employing AGC  
A signal strength meter circuit for an FM radio receiver employing automatic gain control. The signal strength meter circuit includes circuitry for establishing a range of voltages on an AGC line...
4166980 Method and apparatus for signal recognition  
A method and apparatus are provided for sorting signals from compressive receivers in accordance with the type of modulation on the signal, so as to be able to establish the identity of the signal...
4160211 Method and instrument for measuring the sensitivity of a radio receiver  
An RF carrier applied to the antenna input of a radio receiver under test is sequentially modulated with an audio signal to provide sequentially at the audio output of the receiver a signal plus...
4156849 Display device in electrical equipment  
A display device includes a single meter which can be selectively employed as a signal meter indicating a strength level of a received radio wave and an output level meter indicating an output...
4144486 Apparatus for testing metal detectors  
An apparatus and method for testing low-power, low-band radio frequency metal detectors of the type employing a radio transmitter alone or a transmitter and a receiver. The apparatus is...
4128810 Signal level indicator driving circuit  
In a radio receiver circuit provided with an automatic gain control circuit, a tuning indicator driving circuit is connected to a point in the signal transmission line of the receiver circuit at...
4125809 Digital C/kT meter  
A digital C/kT meter for measuring the ratio of carrier power to noise po in a one Hz bandwidth and provide the results to a continuous read-out digital display. The circuit receives an input...
4109206 Signal strength meter drive circuit  
A signal strength meter drive circuit for a radio receiver or tuner comprises a bypass resistor R 3 connected in shunt with the output resistor R 1 of a mirror circuit for an IF amplifier output...
4087750 Receiver for detecting and analyzing amplitude or angle modulated waves in the presence of interference  
This receiver includes in its IF channel a summing network by means of wh the output of a calibrated reference oscillator may be added to the received signals. The frequency and amplitude of the...
4074191 Frequency measuring device for telecommunication systems  
A device capable of being operated under the control of a programmer for rapidly measuring the differences between the actual values of a plurality of transmitted signal frequencies and their...
4068176 Direct reading sinad meter  
The disclosed circuitry accepts from a radio receiver under test audio signals consisting of the signal plus noise and distortion (S + N + D), levels, and subtracts from it a separately generated...
4048564 Transceiver test device  
A device for testing two way radios, particularly Citizen Band mobile transceivers, includes a console with a front panel having meters for displaying rf power, percent modulation, rf voltage,...
4034299 Audio signal quality indicator  
An FM radio receiver with a discriminator having connected thereto a plurality of bandpass filters, each tuned to pass a different portion of the audio spectrum from the discriminator, and...
4031469 Receiver gain calibration  
Receivers with bilateral input stages, such as microwave receivers that are used in noise and RF interference measuring instruments, are gain calibrated in the field by injecting a fixed level...
4006420 Calibratable heterodyne receiver  
A calibratable heterodyne receiver can be adjusted to a calibration mark or similar entity of an indicating device connected to the output of the receiver during feeding of a calibration...
4004230 Critical parameter receiver tester  
A modulated signal is injected into receiver under test. The output of the eceiver is fed directly to a first power measuring device and through a digital filter to a second measuring device. The...
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...
3990011 Method and apparatus for determining AM modulation factor  
The modulation factor for an AM signal wherein the modulation signal is an A. C. wave is determined by demodulating the AM signal, obtaining the average D. C. level and peak deviation therefrom for...
3984862 Television receiver response indicating apparatus  
The overall response of a television receiver is displayed on the face of the cathode ray tube of the receiver involved by test apparatus which requires electrical connection only to the antenna...
3965424 Method and apparatus for tracking an incrementally sweeping generator by a frequency selective receiver  
A method for tracking an incrementally sweeping generator by a frequency selective receiver is disclosed. A sequence of test signals is generated each of which has a discrete and different...
3961264 Linear frequency converter with gain independent of circuit parameters  
A frequency converter circuit includes an input voltage-to-current converter which delivers signal current to a tuned IF circuit via a current steering circuit controlled by a local oscillator. In...
3961260 Apparatus and method for testing the condition of an antenna monitoring system  
A method and apparatus for testing the condition of an antenna monitoring system are provided whereby a sampling loop and coaxial cable assembly may be provided for each antenna element and wherein...
3924189 System for determination of small tuning errors in receivers  
A system is provided for the determination of small tuning errors in receivers, particularly of the SSB (single sideband) type, where the receiver under test is tunable to a plurality of discrete...
3896385 Method and instrument for measuring interference between angle modulated systems  
The interference component resulting from the interference between two angle modulated carriers is obtained without loading the desired carrier. The interfering carrier is equivalently loaded with...
3895191 Method and apparatus for measurement of channel separation in amplifier or the like  
Apparatus and method for measuring channel separation in a transmission circuit having at least first and second transmission channels, the apparatus comprising applying means for respectively...
3885218 Superheterodyne receiver having a digital indication of the received frequency  
A superheterodyne receiver having a digital indication of the received frequency wherein a multi-stage counter serves for measuring the oscillations of a local oscillator by taking into...
3882398 Receiving frequency indicator system for broadcast receiver  
A reference frequency signal is prepared by a fixed frequency oscillator or by multiplying the IF frequency. A receiving frequency representing signal is obtained as an output of the RF amplifier...
3881155 Method and apparatus for detecting the multi-path of FM stereo broadcasted waves  
After receiving the FM stereo broadcasted wave the amplitude modulated component of the intermediate frequency component of the received wave caused by the multipath is detected, and an amplitude...
3875328 Apparatus and method for measuring the signal to noise ratio for a periodic signal  
Apparatus for measuring the signal-to-noise ratio of a television signal wherein the noise and signal level of the signal are derived from the on-the-air television signal horizontal sync pulses....
3871021 3.58 MEGACYCLE BANDPASS AND OSCILLATOR DETECTOR FOR A COLOR TELEVISION  
The invention's purpose is to quickly determine what and to quickly locate where the failure is in a color television receiver, when black and white pictures appear on the screen instead of...
3869673 METHOD AND APPARATUS FOR MEASURING MULTIPATH DISTORTION  
A quantitative approximation of the distortion due to multipath reception of a frequency modulated or other angle modulated signal is obtained by detecting the frequency variations in the received...
3835378 SYSTEM FOR AUTOMATIC GAIN MEASUREMENT  
An automatic measurement of gain is made with an automatic noise figure indicator by adapting the indicator to take the quotient of two parameters of the device under test. Signals representing...
3825835 SIGNAL-TO-NOISE RATIO MEASUREMENT  
System and apparatus for the measurement of signal-to-noise ratio in electrical signals. An adjustable meter is set to the signal level or known fraction thereof and a square wave is added to the...
3774113 APPARATUS AND SYSTEMS FOR TESTING AND MONITORING RECEIVER EQUIPMENT, INCLUDING SYSTEM CAPABILITY FOR CONTINUOUS IN-SERVICE PERFORMANCE MONITORING  
Apparatus and systems for testing and monitoring receiver equipment providing automatic noise figure indication, and capable of continuous in-service performance monitoring. The automatic noise...
3750177 INSTRUMENT LANDING SYSTEM RECEIVER MONITOR  
A phase-amplitude detection system employing a tonal tracer signal imposed on the received ILS carrier signal provides warning as concerns receiver malfunction ahead of the output tone filter...
3743932 CLIPPED CORRELATION TO SIGNAL-TO-NOISE RATIO METER  
A circuit for converting the output of a clipper correlator to signal-to-se ratio in a signal from a sonar array, comprising a primary diode and a capacitor in parallel therewith, and a series of...
3736510 FREQUENCY AND MODULATION MONITOR  
A frequency and modulation monitor for off the air monitoring of aural and visual frequencies of a transmitter in which a frequency synthesizer along with mixers provide a triple-conversion...
3696425 NAVIGATION SYSTEM FOR IMPROVING NOISY SIGNALS  
A navigation system which includes monitoring means for continuously monitoring the navigation signal such that if an intelligent signal varies at an inordinately high rate the rapidly fluctuating...
3691467 DEMODULATING APPARATUS  
Demodulating apparatus for indicating the difference in depth of modulating of a carrier oscillation by two modulating signals of different frequencies f 1 and f 2 comprising an aerial with a...
3651397 METHOD AND DEVICE FOR TESTING APPARATUS FOR SUSCEPTIBILITY TO MAGNETIC FIELD  
Disclosed is improved apparatus and an improved method for use in testing the susceptibility of electrical apparatus to magnetic fields, wherein current is provided to an antenna for producing a...
3643168 SOLID-STATE TUNED UHF TELEVISION TUNER  
A solid-state voltage-controlled capacitor (varactor or varicap) UHF television tuner is described which includes a varicap preselector tuned circuit, a varicap tuned RF amplifier stage inductively...
Matches 151 - 200 out of 230 < 1 2 3 4 5 >