From Oakley Sound via analogue Sent Tue, Jul 16th 2019, 11:12
From Oakley Sound via analogue Sent Tue, Jul 16th 2019, 11:12
One issue that is mentioned in several synth service manuals is that while the charging time is a function of the current source output, the time to reset the sawtooth is determined by the delays in the circuit involved, and is fixed. It does not vary with frequency, although to get the best pitch linearity, the reset time should get longer at low frequencies to match the ramp time, so that the overall period tracks properly. The reset time tends to be very short compared to the ramp time, so the error is small, and mainly affects the higher frequencies. Most VCO's have a special adjustment for higher frequencies that helps to offset the error caused by the fixed discharge time. Since the triangle oscillator ramps up and down with controlled current sources, it doesn't have the problem. Bob --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus