Keysight (formerly Agilent T&M) 44702B 13-Bit High-Speed Voltmeter

The HP 44702B high-speed voltmeter with 64K buffer is a plug-in accessory for the 3852A data acquisition and control unit. It performs DC voltage and ohms measurements at a 100,000 readings/s rate. The voltmeter uses a successive approximation technique for the analog to digital conversion.

The voltmeter has an on-board buffer to store readings. The readings can be transferred to the 3852 internal memory or to a hard disk via GPIO and a DMA controller while making measurements. The 44702B can store over 64000 readings.

The voltmeter resolution is 12 bits plus a sign bit. The volts and ohms ranges can be selected automatically or manually. The voltmeter uses a current source for ohms measurements. The current source is part of the voltmeter circuitry but needs to be externally connected, using a 4-wire ohm configuration, to the volts input terminals of the voltmeter.

• DC voltage
  • Ranges: 40 mV, 320 mV, 2.56 V, 10.24 V
  • Accuracy: 0.05%
  • Resolution: 12 bits plus a sign bit
  • Reading rate: 100000 readings/s with auto-ranging. Signal channel must change no more than 600 V/s during auto-ranging
• Resistance functions
  • 10 kΩ (1 mA current source used): Ranges 40 Ω, 320 Ω, 2.56 kΩ, 10.24 kΩ; Accuracy 0.07%
  • 100 kΩ (100 µA current source used): Ranges 400 Ω, 3.2 kΩ, 25.6 kΩ, 102.4 kΩ; Accuracy 0.07%
  • 1 MΩ (10 µA current source used): Ranges 4 kΩ, 32 kΩ, 256 kΩ, 10.24 MΩ: Accuracy 0.07%
• Resistance reading rate: 100000 readings/s with auto-ranging. Signal channel must change no more than 600 V/s during auto-ranging
• Pacer
  • Programmable intervals: 10 µs to 17 minutes with 0.25 µs resolution
  • Pulse widths: 0.5 µs nominally (low true)
• Noise rejection
  • 40 mV: 90 dB ECMR
  • 320 mV: 80 dB ECMR
  • 2.56 V: 70 dB ECMR
  • 10.24 V: 70 dB ECMR
• Maximum input voltage: All inputs are protected to 16 Vpeak. Input impedance decreases above 12 V
• Bandwidth
  • 40 mV range: 10 kHz (0.1% flatness), 45 kHz (1.0% flatness), 250 kHz (-3 dB bandwidth)
  • 320 mV to 10.24 V range: 15 kHz (0.1% flatness), 55 kHz (1.0% flatness), 400 kHz (-3 dB bandwidth)