8904A Multifunction Synthesizer

  • Sinewaves dc to 600 KHz
  • Square, ramp, and triangle dc to 50 kHz
  • 12 bit direct digital synthesis
  • Tone, DTMF, digital sequence modes
  • One or two outputs
  • One to four internal channels
  • AM, FM, DSBSC phase modulation and pulse modulation
  • External timing control for fast hop

The standard 8904A Multifunction Synthesizer generates accurate sinewaves from 0 to 600 kHz with 0.1 Hz resolution.  The 8904A also has five other standard functions: square, triangle ramp, from 0 to 50 kHz plus dc, and Guassian white noise.  All waveforms in the 8904A are digitally calculated in real time by HP's Digital Waveform Synthesis IC yielding 12-bit digital accuracy.  Full HP-IB programming is also included standard on the HP 8904A

Two Outputs: Option 002 adds a second, identical synthesizer and floating output section to the 8904A.  Frequency, amplitude, waveform, and phase can independently set for the two sources.  Either synthesizer can be precisely varied in phase relative to each other from 0 degrees to 359.9 degrees with a resolution of 0.1 degree.

Complex Signal Generation: Option 001 adds internal synthesizers (for a total of four) which can modulate channel A or be summed to give complex waveform generating capabilities to teh 8904A.  All four synthesizers are independent with precise phase offset capabilities.  The synthesizers can be digitally summed before being output.  In addition to summing, option 001 allows channels B, C, and D to modulate channel A with AM, FM, phase modulation, DSBSC, or pulse modulation.

FM Stereo Composite Mode: Option 001 also includes a mode for generating FM Stereo composite signals.  Test signals in this mode include Left-=Right, Left=-Right, Left Only and Right Only.  Single keystrokes select test tone frequency, composite level, test signal mode, and pilot ton level.  Stereo separation is typically better than 65 dB.

Communication Signaling: Option 001 also adds four sequence modes to the 8904A: tone, DTMF, digital, and hop ram sequence modes.  These modes make the 8904A a powerful tool for use in communication signaling.  Tone and DTMF modes allow creation of single or dual tone sequences up to 750 states in length.  Digital sequence mode can generate bit streams up to 3000 bits in length with 100 usec resolution.  Hop ram sequence modes allows sequencing  of 16 tones, each with an associated amplitude, frequency, and phase value.  Option 003 adds the ability to externally hop Channel A in frequency, phase, or amplitude.  Up to 16 frequency/phase/amplitude states can be entered into the "HOP RAM" memory.  To hop, an external device must address the four-bit wide, TTL-level address bus provided on the rear panel.  Phase continuous switching can be done in as little as 20 usec.

Fast Hop: Option 003 adds the ability to externally hop channel A in frequency, phase, or amplitude.  Up to 16 frequency/phase/amplitude states can be entered into the Hop Ram memory.  To hop, an external device must address the four-bit wide, TTL-level address bus provided on the rear panel. Phase-continuous switching can be done in as little as 20 usec.

Rear Output: Option 004 moves outputs to rear panel.  Note that the rear output can be reconfigured to standard front output at no additional charge.

Unit-to-Unit Phase Synchronization: With option 005, multiple HP 8904A's can be phase synchronized to provide more than two phase related outputs.  In the synchronous mode, one unit is specified to be the master clock unit and all others are designated slaves.  Two signals are then routed from the clock master unit to all slave units through external low-loss splitters.  To synchronize the units, a phase reset command is given to the master 8904A via HPIB or the front panel.  The total phase error between the units will be larger of +/- 0.1 degree or 60 ns for frequencies 0.1 to 100 kHz.  Up to eight 8904A's may be synchronized.

The following are available from stock:  Each includes Operator Manual and US line cord as well as standard warranty and right of refusal.

8904A Standard unit. SN 2843A01685:(EX condition). Includes Operator manual.  HP 8904A $ 600

8904A /001, 5 units available, Special $ 700 each

8904A /002 (2nd output).  SN 2948A07252 (VG, slight scratch on display).  Includes Operator manual.  HP 8904A /002 $ 900

8904 / 002 /004  SN 2817A00804 (EX condition).  HP 8904A /002 004 $ 1000

8904A /006 (600 ohm output). SN 2948A05166 (VG, slight scratch on display).  HP 8904A /006 $ 900

8904A /002 /006  (2 output channels, one 50 ohm and  one 600 ohm output)  SN 3913A09393 (EX condition)  $ 1200

8904A with options 001, 002, 003, 004  SN 2948A07204 (EX condition)  HP 8904A /001/002/003/004 $ 1500