Using an EXAR XR2206, this generator will produce sine, square, and triangular waves from 10 Hz to 100 kHz. Ul is
the XR2206 chip, R7 controls frequency, and S5 through S8 select the frequency range. U3 produces a TTL-compatible square-wave output, while U3C and D produce a sync signal for scope use. U2 is a frequency/voltage converter that is used to drive analog meter Ml, which reads the generator frequency.