
Model 8904A | Service |
PRINCIPLES OF OPERATION
OVERALL
What the Multifunction Synthesizer Can Do
The HP 8904A Multifunction Synthesizer is a general purpose function generator which can output complex signals based on combinations of six waveforms:
sine | square |
sawtooth | noise |
triangle | dc |
Control over these signals includes: |
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frequency, |
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amplitude, and |
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phase. |
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Signals can (with Option 001) be combined by summation and/or modulation. The modulation formats are:
AM | DSB |
FM | pulse |
@M
Long, complex sequences can (with Option 001) be output based on:
tones
DTMF (Dual Tone Multi Frequency)
digital
Channel A can (with Option 003) be
timing
frequency
amplitude
phase
All of the above signal combinations can (with Option 002) be output to a second port. The output ports can be
How Waveforms Are Generated
Waveforms are generated by a numerical synthesis technique. The heart of the synthesizer is a single digital waveform synthesis integrated circuit (DWSIC). For each channel, the DWSIC generates a continuous stream of numbers which represent instantaneous levels of the waveform. This "digital" waveform is then converted to an analog signal by a