Vertical ramp automatic amplitude control

A method of developing a constant amplitude vertical ramp voltage over a range of frequencies comprising:

• developing said ramp voltage by controlling the charge and discharge of a ramp capacitor from first and second current sources;
• utilizing a comparator circuit coupled to said ramp capacitor and to first and second reference voltages and an injected sync signal for developing a signal for operating said second current source for discharging said ramp capacitor;
• comparing the ramp capacitor voltage to a third reference voltage and developing a DC correction voltage;
• and
• applying the DC correction voltage to said first current source for controlling the charging current supplied to said ramp capacitor.

A constant amplitude vertical ramp generator comprising:

• a charge and a discharge current source;
• a ramp capacitor coupled to said charge and discharge current sources for developing a ramp voltage;
• first comparator means for comparing the voltage across the ramp capacitor with first and second reference potentials;
• means for supplying a sync signal;
• flip/flop means responsive to said first comparator means and to said sync signal for operating said discharge current source;
• second comparator means comparing the voltage across said ramp capacitor with a third reference potential;
• means for generating a DC correction voltage coupled to said second comparator means;
• and
• means for applying said DC correction voltage to said charge current source for controlling the current supplied to said ramp capacitor.