Peak Hold Circuit Research Articles

Multichannel current-mode spectroscopy amplifier in BiCMOS technology with selectable shaping time

A four-channel shaping amplifier for high-resolution spectroscopy has been designed and realized in 0.8 /spl mu/m BiCMOS technology to process the signals coming from a new state-of-the art silicon drift detector composed of four elements. The fifth-order semi-Gaussian shaping function is obtained by means of a novel current mode topology based on current mirrors to amplify the time constants and on a current feedback technique to obtain complex conjugate poles. The proposed shaper allows the user to choose among four possible gains and two possible shaping times. The slow shaping time (500 ns) is intended for best energy resolution measurements while the short one (167 ns) allows high rate measurements. The maximum dynamics for the input signal, coming from any kind of preamplifier, is 400 mV. The output signal can be taken both as a voltage and as a current. We have provided each channel with both a voltage-mode and a current-mode peak-hold circuit. The four current outputs coming from the peak-hold circuits can be multiplexed on-chip to a single output pin. The noise performances are fully comparable with commercial instruments and the measured integral nonlinearity is below /spl plusmn/0.5%.

Simple vocal identification method of porpoise sonar signals using an acoustic data logger and a time depth recorder

Individual identification is needed for the standard behavioral observation. However, the vocal identification of cetacean sound is difficult even using an acoustic data logger attached to the animal, because it is hard to exclude the sounds from a nearby conspecific. This paper shows that simultaneous measurement of echolocation signals and the dive depth of a free-ranging finless porpoise (Neophocaena phocaenoides) enables vocal identification. Echolocation signals of a juvenile finless porpoise were observed with an acoustic data logger attached to the upper posterior side of the pectoral fin by a suction cup. The acoustic data logger had 4.8-kHz sampling frequency and recorded each event of pulse, processed by an amplitude peak hold circuit. Dive depth and swim speed of the porpoise were recorded by another data logger every 1 s. Surface reflection of echolocation signals was clearly detected during shallow dives less than 2 m in depth. The delay time of the reflected signal corresponded with the two-way transmission time from the animal dive depth to the surface. This shows that the signals were from the animal wearing the data loggers.

Ambient noise suppression circuit

An ambient noise suppression electrical circuit to be used with a voice communication terminal comprising a gain control amplifier, whose input is a microphone, and a peak-hold circuit that includes a band-pass amplifier that amplifies a specified frequency range of the output signals of the microphone, a peak detection circuit that produces signals in proportion to the peak level of the output signals of the band-pass amplifier, and a holding circuit that controls reduction of output signals of the peak detection circuit for a specified period of time. The output signal from the peak-hold circuit controls the gain of the gain control amplifier. When a microphone is located far from a mouth and is used under high ambient noise, the present invention makes it possible for the microphone to perform as if it is a microphone which is located in a quality telephone handset that cuts off ambient noise.

Frequency Stabilization of a Semiconductor Laser under Direct Frequency Shift Keying Using the Saturated Absorption Signal

The oscillating frequency of a semiconductor laser was stabilized at the Rb-D2 absorption line under direct frequency shift keying (FSK). The control system equipped with a peak-hold circuit provided the frequency stability of 10-9>σ(2, τ)>10-12 at the averaging time 0.05 s<τ<40 s when the Doppler-limited absorption line was used as a frequency reference. This stability was better than that obtained by the traditional control system without the peak-hold circuit under direct FSK. Using the saturated absorption signal, the frequency stability was improved more than one order of magnitude in comparison with that obtained using the Doppler-limited absorption signal.

A simplified method for selecting a carbon-fiber electrode in pulse voltammetry

A method for selecting a usable carbon-fiber electrode using the equivalent resistance and capacitance is presented. This method uses an instrument with a PC-based look-up table for measuring the electrical characteristics of a carbon-fiber electrode in pulse voltammetry. Using this instrument, the equivalent resistance and capacitance of the carbon-fiber electrode in saturated sodium chloride solution can be obtained. This instrument includes a decade resistance box, a peak current detection and hold circuit, a half peak comparator and a decay duration counter. A look-up table is established by using RC circuits to emulate the electrochemical reaction of the carbon-fiber electrode in pulse voltammetry. The equivalent resistance is obtained from the decade resistance box according to Kirchhoff's law. Then the equivalent capacitance is determined from the decay duration counter reading and equivalent resistance with the look-up table via a PC interpolation program. After obtaining the equivalent resistance and capacitance of an electrode, the values are compared with the usable thresholds. This method provides an effective quality evaluation index of carbon-fiber electrode for the user in order to reduce electrode-induced experimental failure. The method is also available for other kinds of carbon-fiber electrodes as long as their look-up table and desired thresholds are established.

Peak hold monolithic integrated circuit with built-in shaping amplifier for hard X-ray detector

A peak hold monolithic integrated circuit, a pulse shape discriminator (PSD), was designed and fabricated for a hard X-ray telescope of a well-type phoswich counter: Welcom-2. It will be loaded in an X-ray astronomical satellite, the Deep Universe Exploring Telescope (DUET). In order to fit the small area of the satellite, this PSD is manufactured by using a semi-custom bipolar junction transistor LSI. The circuit consists of two shaping amplifiers (100 and 500 ns), with peak hold circuits: a low level threshold comparator with a latch; a high level comparator; an auto reset circuit; and an input signal suppress circuit. Requirements for satellite use such as low power consumption under 200 mW/channel were satisfied. The circuit design and circuit analysis of the PSD have been carried out using the SPICE package. A quantitative measurement of the sample chips was carried out. The integral nonlinearity was measured to be less than 0.2% range, and the drop rate of the peak hold circuit was measured to be 0.2%/ mu s. >

Development of sensing system of piezoelectric ceramics measuring contact pressure distributions. On techniques to increase measuring points and speed.

Improvement techniques of the sensing system proposed in the previous paper are described. By the sensing system, optional contact pressure distributions are measured automatically. In the system, piezoelectric ceramics are used and a special electric circuit is designed to measure electric charge in the material. In the electric circuit, the FET with the integral and peak hold circuits is used to increase the measuring points and speed. A sensing system of 20×10 measuring points and a 2-second measuring time is designed. By using this system, the contact pressure distributions for several problems are measured. The obtained total force and the pressure distributions are compared with the corresponding acting forces and the theoretical values.

A microcomputer-controlled system for measuring reactivity in small animals

A microcomputer-controlled system has been designed for measuring reactivity in small laboratory animals. This system uses a microcomputer to trigger an acoustic signal, which is fed to a loudspeaker through an audio power amplifier. An animal’s acoustic startle response is recorded using a moving-coil loudspeaker as a movement transducer. The transducer output is coupled to a peak-hold circuit that records the maximum voltage generated by the animal’s response. After conversion to digital form, the data for each stimulus presentation are stored and then printed when all trials have been completed.

Development of sensing system of piezoelectric ceramics measuring contact pressure distributions.

In this paper, an automatic sensing system measuring contact pressure distributions is proposed. The sensing material is made of piezoelectric ceramics. To measure electric charge in the material produced by contact pressures, a special electric circuit is designed by using a peak hold circuit. A micro computer (NEC PC-9801) and a multiplexer controller are used to automatically measure the contact pressure distributions. By using the ceramic sensor for 5×5 measuring points, the pressure distributions for several contact problems are measured. The obtained total forces and the pressure distributions are compared with the corresponding acting forces and the theoretical values, From the results, it is recognized that the proposed sensing system is excellent in reliability and durability.

αバックグラウンド除去によるトリチウムガスモニタの高感度化

A cancellation circuit was designed and constructed in order to eliminate signals, induced by α-particles from Rn in air, from output signals of a flow-through ion chamber used in a tritium gas monitor. This cancellation treatments can cause a high sensitivity in tritium gas monitoring.The circuit consists of a differentiating circuit, discrimator, adding circuit, peak-hold circuit, sample-hold circuit and differential amplifier. Pulsed α-signals are separated from tritium β-signals by the differentiating circuit and discriminator. After the shaping of α-signals are formed in the peak-hold circuit with the same decay time constant as that of the initlal α-signals, the α-signals are subtracted from initial signals in the differential amplifier.The test for the system showed that the cancellation cireuit eliminated successfully the effect of α-signals. The cancellation circuit functioned very well not only for isolated α-signals, but also for successive α-signals coming within their pulse widths. The long term stability of the system was obtained by combining the cancellation circuit with a temperature-controlled small-current amplifier. The system can offer the means to detect the tritium-gas concentration below the maximum permissible concentration for exhaust gas.

Simple laser pulse energy monitor

A simple and inexpensive relative energy monitor for short laser pulses is described. The three basic units of this system are an integrating detector circuit, an amplifier, and a peak detector and hold circuit. With this device one can measure optical pulse energies (at 1.06 microm) as small as 1.0 nJ with an electronic accuracy of approximately 1%.

An Example of Processing of Ion Intensity Signals from Mass Filter by Analog Hybrid Computer

An analog hybrid computer EAI 180 has been combined to a quadrupole mass filter UTI-KE 100 C to process the ion intensity signals from the mass filter in analog form without changing the signals to digital form. The combination is made only by receiving mass scanning ramp voltage and ion intensity signals from the mass filter. No other procedure is applied to the mass filter system. Mass selection can be made quite arbitrarily on a CRT screen by comparing the scanning voltage to a reference voltage during the usual high speed mass scanning display(100 msec/300 mass). The ion intensity signals are processed in the logic control and peak hold circuits, then the output signals are summed and/or divided in the analog calculation circuits to give a ratio and/or other quantities. Performance tests have proved the combination works quite well and the new system has followed in real time the quick changes of the ion intensity ratios. The system will be capable of being a new tool in the respiratory gas analysis.

A circuit for measuring maximum negative or positive potentials.

A circiut was designed for measuring maximum negative or positive potentials occurring during an action potential. The basic functional unit is a peak-holding circuit that is reset following each action potential. The output of the circuit is displayed on a digital meter and may also be used to drive a point plotter for a graphic presentation of data.