This is the basic function generator loop in the Run mode and is shown by the double arrows in the
block diagram. Triangle and squarewave are generated simultaneously as shown.
The control logic determines Trig, Gate or Run modes. In Trig or Gate modes the waveform is
clamped by the -2I+ current sources and the diode gate, at a point determined by the Start/Stop
Phase control. A signal applied to Trig In releases the clamp and a single cycle is produced in the
Trig mode or a burst in the Gate mode, the waveform is then clamped again.
To achieve the 1, 10 and 100 ranges the 1k range capacitor is multiplied by 1000, 100 or 10 by the
capacitor multiplier circuit.
The TTL circuit buffers one of the comparator outputs to drive the TTL output socket.
The squarewave shaper converts the comparator output to a current signal and applies it to the
squarewave function switch. The sinewave converter uses the non-linear characteristics of a
transistor pair to convert the triangle wave into a sinewave, which is applied to the sinewave
function switch. The selected function is sent to the pre-amplifier where it is inverted and buffered
and applied to the output amplitude control. The signal is summed with the voltage from the DC
offset control at the output amplifier. This amplifier inverts and amplifies the signal up to 20V peak
to peak to drive the 50 Ohm output socket.
The power supply converts the incoming AC line voltage to the DC rails required by the instrument.
5
