Circuits & Schematics Signal Processing, Filters

Awhile back I published a simple design idea for a thermal airspeed sensor based on a self-heated Darlington transistor pair (Ref, 1). The resulting sensor is simple, sensitive, and solid-state, but suffers from a radically nonlinear airspeed ...

This design for a photonic switch needs more than approximately 70 V at the cathode of a duo-lateral optical position-sensing device. This voltage gets speedy response at longer wavelengths, such as 980 nm. The circuit uses fast transimpedance ...

Intrinsically capacitive transducers and other high-impedance signal sources usually require ac coupling and a buffer amplifier to condition the signal for further processing. Buffers take many forms, but most of them compromise signal quality ...

A classic analog application is the full-wave precision rectifier (absolute value) function. Many variations exist on this theme, each with its own supposed (often rather minor and sometimes downright dubious) advantages compared to competing ...

While choosing an op-amp buffer, some sources of negative supply were considered, because the buffer op-amp had to provide true zero voltage on its output. In reality, a typical rail-to-rail output op-amp isn’t capable of this, it can ...

The bandpass filter circuit shown in Figure 1 features an electronically controlled Q. Q for a bandpass filter is defined as the ratio of the 3 dB pass bandwidth to the stop bandwidth at some specified attenuation. The center frequency of the ...

An interesting variation on the theme of digital to analog converters (DACs) is the digital potentiometer (DPOT). In addition to being able to output a voltage proportional to a digital value when used as a multiplying DAC (MDAC), the DPOT can also ...

Frequent design idea contributor, Peter Demchenko, recently published “Extending the resolution of a peripheral DAC” ( Reference 1 ). In it, Peter describes an inverting dual-supply amplifier circuit that he says is intended “ to ...

By decoding the commands sent by a direct-broadcast satellite receiver that uses the DISEqC (digital-satellite-equipment-control) protocol, you can troubleshoot the commands or simply listen in. Eutelsat Corp offers the DISEqC protocol. The ...

There are several applications in which pulses longer than the set width are to be detected, ignoring the other short pulses. We are familiar with the missing pulse detector circuit, which detects the occurrence of a missing pulse in a pulse train ...