The Realistic PRO-2022 and PRO-2032 are almost identical. There is ample space to modify it with a discriminator output. The FM detector is an MC3361. The baseband audio can be found on pin 9 and TP5.

PRO-2022

Pin 9 and TP5 contain the unfiltered audio

The connection to TP5: resistor and capacitor

Follow the next steps to make the discriminator output:

• Connect a 10 k resistor to TP5
• Connect a 2.2 nF capacitor from the resistor's other lead to ground, e.g. to the metal case of the IF coil
• Connect a short strand of wire to the junction of the resistor and capacitor
• Mount a 3.5 mm chassis socket in the back of the scanner. Connect the wire with the inner contact. Since the back plane is grounded, there's no need to connect the socket's ground lug.

Overview of the discriminator output