In the circuit the frequency trimming component is arranged so that the voltage across it is in quadrature with the voltage V0 from the bridge so that as it is adjusted the attenuation of the bridge only changes a little, avoiding the need for a two gang component. The range of variation of frequency is very limited.
By using a high gain amplifier and metal film feedback resistors the loop gain can be set so that the unit just oscillates and the use of an automatic gain setting component, a thermistor for example, is eliminated.
holds last levelThis Design Idea is a gated with the unusual (unique?) characteristic of stopping in its current state rather than being forced high or low. Unlike a conventional gated , this one both starts and stops in its existing state
EE Times I suggested that he use a -, but he was of the digital persuasion and used a squave , a counter chain, a PROM with the sine conversion lookup table, and a D-to-A. If only he (and me) had known about what you just described.
ElectronicsWeekly.com (blog) I can remember a colleague working for weeks on a sinewave generator board for a piece of test equipment. He came up with a with several refinements that had wonderfully low distortion. To be honest, I can't actu
Designers often use VFCs (voltage-to-frequency converters) to perform A-to-D conversion in data acquisition systems that require strict monotonic response, high resolution, reduced noise and moderate speed. The VFC produces a pulse train with fr
evertiq.com To meaningfully test 18-bit A→Ds, the must have transcendentally low levels of impurity, and these characteristics must be verified by independent means. Figure 2 is basically an “all inverting” 2kHz design (A1-
uses solar cell junction capacitanceAny PN junction diode can be used as a variable capacitor in reverse biased mode, as well as in the forward biased mode before the knee voltage. The capacitance is usually very small as the junction size
EDN.com works on low supply voltagesThis sawtooth- circuit, drawing less than 3.2 μA and working at under 1V, is a useful building block that fits the bill for extremely low-power consumption and operation to low supply voltages. It c
EDN.com -You can't measure 90-dB distortion and noise using sources that are “60 dB-ish.” So rather than try to find and keep an almost-ideal programmable signal generator, I decided to build up a low-distortion Meacham-bulb-s
EDN.com A typical voltage-to-frequency converter—also known as a VCO (voltage-controlled )—IC has a simple linear tuning characteristic relating input voltage to output frequency. It is usually of the form F=kV/RC, where RC is