A Comparator to Use on Bad 2068 Tapes

The program loading end saving process on the TS2068 is e great improvement over the TS1000. The signal recorded is a series of square pulses, with ones shorter than zeros. There is no DC component and reversing plus and minus has no important effect. Square waves are difficult to record and some tapes are being sold that may not load.

A tape would have to be in really dreadful condition before the point where the signal changed from plus to minus was effected. A handy electronic circuit known as a comparator is specially designed to take a bad square wave and make it into a good square wave. An ordinary op-arp makes a good comparator for our purpose. While an LF353N was used in our example, any op-amp that will work at low voltage is suitable.

A comparator is a very high gain amplifier whose output is designed to go from one extreme of the power supply to the other. Think of it as a constantly overloaded amplifier and a one bit A to D converter. The output is equal to the power supply voltage, the values of the components are not critical, so don’t be afraid to experiment.