Abstract:
The invention refers to single-ended test of a loop with the aid of a transceiver, wherein an input impedance (Zin(ƒ)) of the loop is generated. The transceiver has a digital part, a codec and an analog part and is connected to the loop. With the aid of a transmitted and a reflected broadband signal (vin, vout) an echo transfer function Hecho(ƒ)=V(f)out/Vin(f) is generated, which also can be expressed as H echo ( f ) = H ∞ ( f ) Z in ( f ) + Z h0 ( f ) Z in ( f ) + Z hyb ( f ) . Here Zh0(ƒ), Zhyb(ƒ) and H∞(ƒ) are model values for the transceiver. In a calibration process a test transceiver, with the same type of hardware as the transceiver, is connected to known impedances, replacing the loop. Hecho(ƒ)=V(f)out/Vin(f) is generated for the known impedances and the model values are generated and are stored in a memory in the transceiver. The stored model values are then used when the input impedance (Zin(ƒ)) for the loop is generated after a measurement of the broadband signal (Vin, vout) is performed.
Abstract:
A gas-measuring device has an electrochemical sensor and features such that the readiness for use is guaranteed for a determined period of time. A status display (7), is activated by the evaluating circuit (3) of the gas-measuring device. The status display (7) displays the degree of depletion of the sensor.
Abstract:
A sensor signal processor includes a scale having optically or magnetically fine divisions; a detection sensor that moves with respect to the scale and that is provided in association with the divisions of the scale; and a position detecting unit for calculating positional information by using a counter value of digital pulse signals generated from the outputs from the detection sensor and analog signals generated from the outputs from the detection sensor. The sensor signal processor yields the positional information by using both the digital pulse signals and the analog signals.
Abstract:
In an optical measuring apparatus so structured as to hold a CCD camera and a laser displacement gauge so that they can be three-dimensionally driven at the same time on a stage, a jig including two straight, non-parallel line segments which can be measured by the CCD camera and the laser displacement gauge in the projection plane along the Z-axis direction is mounted on the stage; the straight line segments are measured in the projection plane by the CCD camera and the laser displacement gauge to obtain formulas of these segments; the obtained formulas are subjected to the arithmetic operation to calculate an offset value of the X and Y plane coordinate centers between the CCD camera and the laser displacement gauge; and the offset value is used as position calibration data of the CCD camera and the laser displacement gauge to perform position calibration of the measurement data.
Abstract:
The method of acquiring, calibrating and storing measured weight data in a secure manner and of acquiring and storing other non-calibratable measured data for display and processing includes providing calibratable weight data acquisition devices (2) and at least one non-calibratable data acquisition device (2) for non-calibratable data other than weight, providing an approved calibrating device (1) in non-interacting dialogue with each data acquisition device, wherein the approved calibrating device includes a computer (3) including a first driver (I,8), a second driver (II,10), a monitor (5), a memory and an EEPROM card (11); triggering the data acquisition devices (2) to obtain calibratable measured weight data and non-calibratable data besides weight; providing the measured weight data and non-calibratable data with references by means of the first driver (I,8), the second driver (II,10) and the EEPROM card (11) during transfer by the approved calibrating device (1); calibrating the measured weight data to obtain calibrated measured weight data; buffer-storing the calibrated measured weight data and the non-calibrated data in a manipulation-proof and non-erasable form on the EEPROM card (11) and transferring the buffered calibrated weight data from the EEPROM card (11) to the memory of the computer (3); whereby the buffered calibrated weight data is available for retrieval at any time in any order and current measured weight data and current non-calibratable data from the data acquisition devices (2) are retrievable in any order by the computer for display on the monitor (5).
Abstract:
A front-end architecture is provided for a measurement instrument having a single path for the input signal for conversion into digital samples. A signal conditioner may be coupled via a pair of test leads across a voltage source, current source, or component to develop an input signal. The input signal is provided to a sampling system, which comprises a sigma-delta converter followed by a decimation filter, which over-samples the input signal to produce a continuous stream of digital samples. The digital samples are provided to a set of digital extraction filters, each digital extraction filter having a structure and transfer function adapted for extracting a measurement parameter from the stream of digital samples. Parameter extraction is performed on a continuous basis so that the digital samples and the resulting digital measurement values arrive in a continuous stream. Extracted parameters include the d.c. value of the input signal, the rms value of the input signal, the waveform parameters of the input signal, and the peak min/max values of the input signal.
Abstract:
A microcontroller for use in battery charging and monitoring applications is disclosed. The microcontroller includes a microprocessor and various front-end analog circuitry such as a slope A/D converter and a multiplexer for allowing a plurality of analog input signals to be converted to corresponding digital counts indicative of signal level. In order to make the measurements of the selected analog inputs more precise, the microcontroller uses a unique calibration procedure whereby selected parameters associated with the analog circuitry that are subject to variation are measured during test and corresponding calibration constants are calculated therefrom and stored in program memory. These stored calibration constants are subsequently used by the microprocessor in conjunction with the digital counts of the analog input signals for calculating a more precise measurement of the analog input signals.
Abstract:
An automatic guitar string tuning device includes a foot-operated switch for controlling an electrical solenoid which rotates a cam shaft mounted upon a guitar or other stringed instrument. The solenoid rotates the cam shaft between first and second positions under the control of the foot switch. Several of the guitar strings are secured to tensioning arms which engage corresponding camming surfaces formed upon the rotating shaft. Rotation of the cam shaft between the first and second positions causes movement of the tensioning arms and thereby changes the pitch of the strings attached thereto.
Abstract:
Rotational speed of a vehicle speed detecting gear 1 is detected by a detection element 2 using an MRE or the like and the detected signal is waveform-shaped by a waveform shaping circuit 3 to serve as a vehicle-speed pulse signal. The cycle of the vehicle-speed pulse signal is detected by a sampling circuit 4. The detected cycle of the pulse signal is multiplied by a predetermined multiplier in a multiplication circuit 6 and the multiplication result is divided by a predetermined divisor in a diving and pulsing circuit 8. Then, a pulse signal having the cycle equivalent to the division result is output as a divided vehicle-speed pulse signal.
Abstract:
To compensate for quasi-periodic disturbances in measurement signals, the wanted signal is separated from the disturbing signal by determining from an auxiliary signal a series of trigger instants, and estimating from this measurement signal a disturbing signal template, by furthermore generating from this disturbing signal template a trigger-synchronous reference signal, and by using this trigger-synchronous reference signal for filtering the measurement signal. The process can be carried out both after the recording of a complete measurement data set and at the same time as the recording of such a measurement data set. The process is suitable in particular for compensating for cardio-interference during magneto-encephalography.