LED output from SB Live! Value

Many modern audio recorders is now compatible with digital input S / PDIF (Sony / Philips Digital Interface). Devices like CD Changers, MiniDisc recorders, computer sound cards and the like. working with digital signal just with protocol S / PDIF. Digital connection of two devices, for example. sound card with MiniDisc avoiding D / A converter cards and A / D converter minidisc they bring to the useful signal to noise ratio and cause a linear, harmonic and nonharmonic distortion. Sound Card SB Live! Value is equipped with a digital output in a yellow 3.5 mm connector labeled DIGITAL OUT.
LED output from SB Live! Value - schematic

The signal from this jack is activated Software (Creative Mixer) set output to Digital Only. This signal is not compatible with TTL, is adapted for coaxial cable transmission (bipolar signal). Since I needed to connect your sound card with the MiniDisc, which has optical input, so. TOSLINK, I had to check the parameters of the optical signal. Important is the light intensity and wavelength. Optical connectors (eg TOTX from Toshiba fy) are relatively expensive and difficult to hunt. In practice meets vysokosvietivá 5 mm red LED. I also tried the IR diode is useless. Optical cable must be in the axis with the axis of the LEDs and as closely as possible. For these reasons, I made an optical connector with LED on exactly the piece of plastic fiber optic cable connector. Since the LED is at a voltage of about 2.5 V and current needs about 20 mA, I made a very simple digital converter card bipolar signal from the TTL signal, which is driven LED. Digital signal (conc tip jack) is fed through the input capacitor ode?ovací inverter 7404, to which also brings the bias divider formed trimmer 10k. This bias sensitivity of the entry. Output from the first inverter is connected to the parallel combination of 5 inverters, which together provide sufficient current for LEDs. The connection can be used conventional integrated circuit with 6 gate MH7404, 74HC04 or CMOS 4069th Supply voltage +5 V I brought from the USB connector on the...

Leave Comment

characters left:

New Circuits