Comparator applications

About: Comparator applications is a research topic. Over the lifetime, 2518 publications have been published within this topic receiving 26639 citations.

Parallel analog-to-digital converter circuit

Abstract: A parallel analog-to-digital converter circuit comprises a plurality of level comparator circuits (10) and a plurality of detector means (52). The level comparator circuits (10) compare the level of one analog input signal with a plurality of reference levels. Any two or more level comparator circuits (10) which receive consecutive reference levels from one set. Each of the detector means (52) determines whether or not the output signals from the level comparator circuits (10) of one set are in a specified state. According to the number of sets of level comparator circuits (10) whose output signals are detected to be in the specified state, it is determined whether or not the analog-to-digital converter circuit functions correctly. The upper limit of the speed of analog-to-digital conversion can be determined according to this number of sets.

Nonquadrature correction circuit

Abstract: A phase comparator has additional circuitry for correcting nonquadrature error during operation of the comparator. The phase comparator has a 90 degree power divider which receives a reference signal input and produces two reference outputs, one shifted 90 degrees out of phase with the other. The phase comparator also has a zero degree power divider which receives a return signal, such as a reflected signal of a radar transmitter unit. The outputs of the power dividers are applied to mixers and filters to result in an I video output whose frequency is the difference between the reference and signal input frequencies, and a Q video output which is identical in frequency but shifted 90 degrees. The correction circuit includes a frequency trap connected to the reference input and tunable about a center frequency of approximately the third harmonic of the fundamental reference frequency. While the phase comparator is operating, the trap is detuned from the center frequency while the phase error is monitored until the phase error nears zero. Band pass filter means which electrically isolate the power divider from external circuitry can improve operation.

Digital BFO metal detecting device with improved sensitivity at near-zero beat frequencies

Abstract: An improved metal detecting device of the beat frequency oscillator type is provided which incorporates a method for determining the side of the zero beat frequency at which a search oscillator is operating. The device includes a search coil conveniently mounted which is part of a search oscillator. A reference oscillator is also provided, the output of which is digitally compared to that of the search oscillator by a digital phase comparator. The digital phase comparator output is applied through a low pass filter to a slope detector circuit. The slope detector output signal is supplied to both an audio output circuit and a filter/comparator. The audio output is sufficient to facilitate location of permeable and conductive substances. The output of the slope detector also contains information which is extracted by the filter/comparator and translated to an audible signal by an oscillator and the audio output circuit. This audible signal serves to facilitate the determination of whether a permeable or a conductive substance is being detected.

Electronic safe and arm apparatus for initiating a pyrotechnic

Abstract: An electronic safe and arm apparatus disposed in a projectile having a spin axis and a spin rate includes a battery; a power supply board connected to the battery, the power supply board including a mechanical G-switch that closes permanently at a predetermined acceleration, and a time-delay circuit connected to the G-switch; a firing board connected to the power supply board, the firing board including: an accelerometer that is oriented perpendicular to and disposed a fixed distance from the spin axis, an output of the accelerometer varying according to the fixed distance from the spin axis and the spin rate of the projectile; a comparator connected to the output of the accelerometer wherein the comparator compares the output of the accelerometer to a threshold voltage and an output of the comparator is low when the output of the accelerometer is less than the threshold voltage and the output of the comparator is high when the output of the accelerometer exceeds the threshold voltage; a rectifier connected to the output of the comparator; a firing capacitor, the rectifier being connected between the battery and the firing capacitor whereby when the output of the comparator is high the comparator saturates a gate of the rectifier thereby allowing the firing capacitor to charge; and an initiator connected to an output of the firing capacitor; and a timing board connected to the power supply board and the firing board, the timing board for setting and controlling a predetermined time delay for discharge of the firing capacitor into the initiator.

Voltage drop circuit

Abstract: A voltage drop circuit includes a comparator for comparing a predetermined reference voltage and a generated internal voltage, a first current supply unit for being activated in accordance with an output of the comparator, a level converter for converting the output of the comparator to a CMOS level, a second current supply unit for being activated in accordance with an output of the level converter, and a load circuit for receiving current from the first and second current supply units and forming an internal voltage.