Technology of Q 2500 colour TV set

Technology of Q 2500 colour TV setOn the Dolby Digital Module the two surroundchannels are muted via transistors Q 8/Q 4/5and Q 6/7. If a data error is detected on theDolby Digital Module during digital sound signalprocessing, pin 30 on I 01 outputs H level.Via the two transistors Q 9 and Q 10 the mutefunction is then activated. For the mute functionthe Dolby Digital Module represents bothinput and output.As you can see from the mute circuit, somesounds have an output line, as, for example,for the LFE channel Q1552/56, two transistorsare used. This measure improves the mutebehaviour and the error rate of these stages.5.2.16 Headphone amplifierAs in previous models the front panel of thedevice has a connector for headphones. Asfor the loudspeaker branch the signals arealso generated in the MSP 3411. As alreadydescribed, the loudspeaker control for theheadphone control is also implemented in it.These signals are output in pulse width modulatedform on pins 24 and 26 of the MSP andintegrated with external RC components intoan VF signal at up to 1.2 Vss. They are fedrespectively to an amplifier stage, consistingof 2 transistors Q 1441/46 and Q 1461/66.This stage amplifies them to 9 Vss and outputsthem via a decoupling through C 1448/68to the headphones socket and pin 2/4 on pinconnector W 1431 for the HF transmitter.The headphones volume can be controlled in63 stages and the setting displayed on thescreen.Document Q 2500 119 © Loewe ProCollege