Circuits & Schematics - Audio - 2

When a system's specifications call for a lowpass filter with a steep frequency-cutoff characteristic, an engineer can opt for a “brick-wall”- filter design that features a sharp transition band. For example, in an FM ...

At the end of the DI for a Simple log-scale audio meter (Ref. 1), I promised to show how to upgrade it to work better. With these fixes, it now has near-digital performance, with faster response and smoother operation. Even this supersized version ...

While refurbishing an ageing audio mixer, I decided that the level meters needed special attention. Their rather horrible 100 µA edgewise movements had VU-type scales, the drive electronics being just a diode (germanium?) and a resistor. ...

A question that arises frequently in audio and signal processing applications is this: How can I control gain on dual channel (e.g., stereo) inputs simultaneously with only a single knob? Of course, an obvious solution would be to simply use a dual ...

Low-frequency filters, particularly at audio frequencies, usually take the form of active filters. These filters eliminate expensive inductors with windings of many turns. Both analog and digital active filters are most compatible with large-scale ...

The sample and hold circuit (Figure 3) is considerably more complex than the oscillator. This is unfortunate but unavoidable. It's the S/H that gives this design its speed (fast settling time) and very low distortion, and it's very unlikely ...

Introduction As discussed in the article [ 1 ], although a sinewave is the simplest possible waveform, it is also one of the hardest to generate in pure form. Any impurity represents distortion, and that means added harmonics that make very low ...

Many amplifiers, including integrated devices, are afflicted with undesired, implicit input terminals in their power connections. Due to less than perfect power-supply rejection, these implicit terminals admit noise into the signal that the ...

An audio volume-unit meter displays peak-related audio amplitudes to aid in accurately setting recording levels or for displaying an amplifier's operating conditions. A simple diode and capacitor network provides a classic volume-unit ...

Amplifying the human voice presents some tough challenges. One of the toughest of these is providing enough amplification to make sure a soft-spoken person can be heard while allowing sufficient headroom for people who speak loudly. If the ...