Controler de volum si selectie sursa audio cu ATMEGA32
Vicol-Audio volume controller offer important sonic advantages over common potentiometers due of discrete resistors and method of signal attenuation: resistor voltage dividers. Discrete resistors offer better low noise and characteristics than the carbon or cermet resistor elements used in potentiometers. Vicol-Audio volume controller make use of low tolerance, noninductive, professional MELF resistors for R-2R/Shunt attenuation network.
MELF is the acronym for Metal Electrode Leadless Face – a leadless cylindrical component that is metallized on two ends. It is designed majorly as a SMD (Surface Mounting Device) component. Since manufacturing process of MELF resistor is more complex than flat-chip resistor, MELF resistor has its own advantages over flat-chip type.
Compared with regular flat-chip type SMD resistors, MELF offer low TCR (typical lower than ±5ppm/°C), greater surge handling, low noise and ultra low distorsion, ensuring high stability through time and over temperature variations.
The total measured resistance for each position of our volume-controller remains constant throughout years of use. This is because the wearing (rubbing) parts in Vicol-Audio volume controller are low resistance switching relays, not resistive elements with wipers sliding on them as in potentiometers. Potentiometers can add clicks, pops, and noise to wear.
Stereo potentiometers used as volume controls often produce different volume levels for each channel, and the amount of mismatch can vary as the potentiometer is turned up or down. The channel-to-channel tracking specification for stereo potentiometers, even very expensive ones, is typically 5% to 20%. With Vicol-Audio volume controller you can easily achieve stereo signal levels matched up to 0.1%.
Outstanding S/N ratio and excellent THD of the amplifier is not compromised in any way, and the same superb sound quality will be obtained at any volume setting. Signal level has been pre-determined for each step, so front panel display can represent actual signal levels.
vezi continuarea aici: http://www.mikroelectronica.ro/2012/07/controler-selectie-surse-volume-by-danzup-fw-v2-3/