HP8904A Multifunction Synthesizer

Purchased on eBay -- eBay 8904A search

Can use a 10MHz external reference.
0.1Hz - 600kHz. Sine and noise.
0Hz - 50kHz Square, Triangle, Ramp.
DC. +/- 10V Open circuit
Four independent synthesizers, channel A, B, C, & D. (B, C, & D with option 001)
Two outputs, Output 1 & 2. +/- 10V p-p 50 Ohm load. (one output without option 002)
Modulation: AM, FM, Phase, Double Sideband, Supressed Carrier, & Pulse. (with option 001)
NO external modulation.
Fast hop digital modulation. (with oprion 003)
FM stereo, Tone Sequences, DTMF sequences, Digital sequences.
Option 001, 003, and 005 can be enabled from the front panel. Option 002 & 006 require additional hardware.
Option 004 moves outputs to back panel.
Option 005 enables synchronization between multiple units.
Option 006 changes output 1 to a 600 Ohm balanced output

1kHz, Harmonics