Multiple waveform signal generator

The circuit, shown in the attached figure, utilizes a six-inverter digital integrated circuit, the 74HCU04, capable of simultaneously outputting rectangular, triangular, and sine wave signals, with a continuously adjustable frequency between 10Hz and 1MHz. A through F represent six inverters. A and C1 form an integrator, while B, C, R2, and R3 form a Schmitt circuit. When the Schmitt circuit's output signal is fed back to the integrator's input via R1 and RP1, a square wave oscillator is formed. The oscillation frequency can be approximately expressed as follows: fosc = 1/4 [(R1 + RP1) C1] (R3 / R2). Adjusting RP1 changes fosc. If the minimum oscillation frequency is set to 1, the oscillation frequency can be continuously adjusted between 1 and 20 times. The relationship between C1's capacitance and the oscillation frequency fosc is shown in the attached table.

F, R4, RP2, and R5 form a linear inverting circuit. Four diodes, VD1 through VD4, form a bridge circuit. This limits the top of the triangle wave, converting it into a sine wave. Adjusting the value of RP2 minimizes the distortion of the sine wave.