1kHz Ultra Low Distortion Oscillator Module for Arduino Projects

This is an extreamly low distortion 1 kHz oscillator module for Arduino controlled projects.

The module will be used in my ref. signal source design.

Main parts:

Opamps: LT1115 - LT1638 - OPA2134

FET: 2N4391

The BurrBrown OPA2134 is critical for the distortion specification.

To get 1kHz very precise C1, C2, R2, R7 must be selected very carefull.

The measured specification of the module:

Frequency:           1036 Hz (before using selected parts for C1, C2, R2, R7)

Signal level:          1000 mV rms / 0dB

Distortion:             0.0003% / - 111dB

Signal/noise:          - 91.1 dB

The design is based on a state variable oscillator.

(Ref.: http://vkaudiotest.co.uk/ --- BUT this link is no longer active and I have not been able to find the original circuit designer).

The circuit diagram: there are 3 main circuits. The state variable oscillator, full wave rectifier and the precision signal stabilization circuit.

The PCB layout for the module is based on my prefered dimensions for modules. The modules will be build in a standard Hammond box.

This is the project where the 1khz module is used.

More to come of the design of the complete test equipment.

The intention on the test equipment: Testing of audio equipment