The digital sine wave generator (oscillator) circuit has the advantage that only few components are needed to generate signals with high amplitude constants and variable within a very wide range of frequencies. The circuit shown here generates a sinewave signal. Other signal forms can also be generated by changing the values of R1…R8.
After the power supply is connected to the circuit, the combination R9/C1 generates a short reset-pulse and all outputs if the 4015B are set to logic 0. The oscillator is controlled by an external clock. The frequency of the sinewave is 1/8 of the clock frequency. The highest frequency of CMOS ICs is 7 MHz, therefore a sine wave signal of 500 kHz maximum can be generated.
A 555 clock generator can be used to drive the register IC. A square wave signal with the same pulse width and frequency comes out from Din pin of the 4015B. It can be used as a trigger signal for an oscilloscope.