DDS #2 on test

Today I continued with the development of the second prototype frequency synthesiser. I have added the facility of changing the tuning step size in real time.
It is shown being tested on the work bench alongside "MyDev2", ( PIC18F4550 microcontroller ), and "ICD2", ( debugger and programmer ).
The output voltage at 137.7KHz is a 1.32v peak to peak pure sine wave across 300 Ohm. There is no output low-pass filter and I think this is the reason the output level is about twice that of prototype #1, which incorporates such a filter, probably introducing significant residual capacitive reactance.