Infra-red transmitter

Infra-red transmitter: It often happens that someone wants to watch television without the sound disturbing other people in the room. To avoid having a long cable trailing over the floor, the present transmitter (and accompanying receiver ) make it possible to listen to the TV sound wirelessly. The transmitter uses pulse-duration (=pulse-width) modulation. The modulated[…]

Read more

Infra-red headphone receiver

Infra-red headphone receiver: This receiver is meant to complement the transmitter describe in the previous article. Its design is based on just one FET. This has the advantage that construction is simplicity ‘itself, and the disadvantage that for a sufficiently low output impedance the value of drain resistor R3 has to be fairly low. That results with[…]

Read more

Active bass correction

Active bass correction: Active loudspeakers offer the only way of obtaining good bass reproduction from inexpensive or small enclosures. The design described does not make use, therefore, of large, heavy enclosures to obtain a good result, but of acoustic feedback. A microphone placed close to the bass drive unit unfailingly registers every movement of the loudspeaker.[…]

Read more

Digital volume control

Digital volume control, Two ladder networks and a buffer each from a volume control with a range of 63 dB. Network R3-R17 provides fine control in steps of 1 dB, whereas network R20-R34 provides coarse control in steps of 8 dB. The desired attenuation is set with aid of multiplexers IC1 and IC3, each of[…]

Read more
1 2 3