Circuits & Schematics - Signal Processing, Filters - 3

The isolation amplifier circuit of Figure 1 is simple but accurate. With the values shown it converts 0 to 5 V DC or low frequency signals with unity gain, but you can adjust the gain by changing R4. Figure 1. The floating sigma-delta converter U1 ...

At least two classic ways exist to address applications requiring sampling of a sum of analog voltages. The most common way is to cascade a classic analog adder and a sample-and-hold amplifier. A classic analog adder is an op amp plus at least ...

Pulse width modulation (PWM) is a simple and inexpensive (therefore popular!) way to implement moderate performance (e.g., 8 bit resolution low speed) digital to analog conversion, but improvising cheap DACs isn’t the only thing PWM can do. ...

Many industrial- and medical-system circuits require isolation from the mains-ac power. You can often send a signal across the isolation barrier using a small transformer; transformers do not pass low-frequency signals well. The circuit in this ...

Positive feedback is a typical technique for distributing hysteresis around a comparator, provided that you have a resistive path between the comparator's output and the noninverting input. Positive feedback forms two threshold voltages that ...

Professional electronics designers often use peak-detector circuit sin such applications as amplitude measurement, automatic gain control, and data regeneration. You can build a simple and fast peak detector from a serial diode and a shunt ...

You face a serious problem in using a slow ADC with a fast peak detector. The circuit in Figure 1 allows a slow ADC to measure a fast, sampled signal peak. The 100-MHz peak detector for ultrasonic-pulse sampling uses a fast MAX4231 amplifier. This ...

Sometimes, you need to distinguish between two voltages, using some hysteresis in the decision. When the levels of the compared signals vary over a wide range (for example, a few orders of magnitude), the hysteresis width should vary similarly to ...

Although monolithic instrumentation amplifiers are more cost-effective than their discrete and modular predecessors, the limited variety of monolithic instrumentation amps restricts their use. You can widen your options, however, by deriving the ...

Modern battery-cell voltages of 3 to 3.6 V require circuits that offer efficient low-voltage operation. This Design Idea proposes an ac-coupled instrumentation-amplifier design that features high CMRR (common-mode-rejection ratio), wide dc ...