HP 3325A Synthesizer Function Generator

The HP 3325A Synthesizer Function Generator generates signals with minimum frequency of 1µHz and the following maximum frequencies:

• Sine Wave 20 MHz

• Square Wave 10 MHz

• Triangle 10 kHz

• Positive slope ramp 10 kHz

• Negative slope ramp 10 kHz

The frequency can be selected from 11 digits. Output amplitude can be adjusted from 1mV to 10V peak peak and can be selected and displayed either in V rms or dBm (50 ohms). Possible also an DC offset of +/-4.5 V. The high output voltage option 002 (like the shown device) can supply a 40 Vpp in to >=500 ohms load. Also very usefull the option 001 a High Stability Frequency Reference a quartz inside a temperature controlled oven. Of course the instrument has an HP-bus interface and analogue and digital outputs for many applications.

The HP3325A instrument is a nice general purpose generator leaving not many wishes open, ideally for electronic development. Testing slew rate of an audio amplifier by using the clean steep sqaure wave signal. The high voltage option is very usefull to test power amplifier without the need of a preamplifier. 

No circiut designer want's to miss the instrument - really.

HP 3325A simplified specification (taken from a 1984 manual):

Frequency Resolution:

• 1µHz for frequencies below 100 kHz and 1mHz for frequencies 100 kHz and higher

Frequency Accuracy standard instrument:

• +/-5 * 10 exp -6 of selected value (20°C to 30°C) 

Frequency Stability standard instrument:

• +/-5 * 10 exp -6 per year (20°C to 30°C)

Signal Characteristics:

Sine Wave and harmonics: 

• 0.1 Hz to 50 kHZ: no harmonic greater than -65dB
• 50 kHz to 200 kHz:  -60dB
• 200 kHz to 2 MHz: -40dB
• 2 MHz to 15 MHz: -30dB
• 15 MHz to 20 MHz: -25dB

Square Wave:

• Rise and Fall TIme: <= 20 nanoseconds, 10% to 90% at full output

Triangle:

• Linearity, 10% to 90%, best fit straight line: +/-0.05% of full p-p output for each range

Ramps (positive or negative):

• Linearity, 10% to 90%, best fit straight line: +/-0.05% of full p-p output for each range

Amplitude Accuracy [no Attenuator (in Range 1) in 50 ohms and no DC offset]:

• Sine Wave 0.001 Hz to 100 kHz accuracy relative to programmed amplitude +/-0.1dB
• Square Wave 0.001 Hz to 100 kHz accuracy relative to programmed amplitude +/-1.0%
• Triangle 0.001 Hz to 2 kHz accuracy relative to programmed amplitude +/-1.5% (+/-5% for 2 kHz to 10 kHz)
• Ramps 0.001 Hz to 500 Hz accuracy relative to programmed amplitude +/-1.5% (+/-10% for 500 Hz to 10 kHz)

Amplitude Flatness [no Attenuator (in Range 1) in 50 ohms and no DC offset]:

• Sine Wave 100 kHz to 20 MHz accuracy relative to programmed amplitude at 1 kHz +/-0.3dB
• Square Wave 100 kHz to 20 MHz accuracy relative to programmed amplitude at 1 kHz +/-10%

Amplitude Modulation:

• Sine Wave only, Modulation Envelope Distortion: -30 dB to 80% modulation at 1 kHz, 0V DC offset

Phase Offset:

• Range: +/-719.9° with respect to arbitrary starting phase. or assigned zero phase. Resolution: 0.1° Stability: +/-1° phase/°C

Phase Modulation:

• Linearity (Sine Function): +/-0.5%, best fit straight line

Synch Out (into 50 ohms):

X-Drive Output:

• Amplitude 0 to dc 10V linear ramp proportional to sweep frequency (sweep up only)

Option 001 High Stability Frequency Reference:

• Ambient Stability: +/-5 * 10exp-8 (0° to 55°C referenced to +30°C)
• Aging Rate: +/-5 * 10exp-8 per week (after 72 hours continuous operation)
• Aging Rate: +/-1 * 10exp-7 per month (after 15 days continuous operation)

Option 002 High Voltage Output:

• Frequency Range: Sine and Square Wave: 1 µHz to 1 MHz
• Triangle and Ramps: 1 µHZ to 10 kHz
• Amplitude Range: 4mVp-p to 40Vp-p (>=500 ohms, <500pF load) maximum output current +/-40mA
• Amplitude Accuracy: (at 2 kHz) +/-2% of full output for each range
• Amplitude Flatness: +/-10% of programmed amplitude
• DC Offset: 4 times the range of standard instrument
• Harmonics: (under full load) 10 Hz to 50 kHz, no harmonic greater than -65dB
• for 50 kHz to 200 kHz -60dB and 200 kHz to 1 MHz -40dB.
• Square Wave: Rise/Fall Time <=125 nanoseconds, 10% to 90% at full output with >500 ohms and <500 pF load
• Overshoot: <10% of peak amplitude with same load.

         Hier ein Reparatur Bericht solch eines Gerätes von Markus