Model 7310
Noise Rejecting Voltmeter

Model 7310 Noise Rejecting Voltmeter

General
The model 7310 Noise Rejecting Voltmeter is a flexible instrument designed to offer the engineer or scientist the ability to measure signals that are accompanied by unwanted noise or interference.

The unit can best be visualized as a digital filter, implemented using the latest digital signal processing (DSP) techniques, followed by a true rms to DC converter and digital meter. The filter can be configured as a bandpass stage with adjustable center frequency and Q-factor, as a low-pass filter with adjustable cut-off frequency or bypassed for broadband measurements. A separate analog line-frequency rejection filter adds yet further filtering flexibility.

Input signals may be from single-ended or differential voltage, or single-ended current sources. After amplification, but prior to the digital filter, the discrete Fourier transform of the applied signal and noise can be calculated and displayed graphically on screen. This spectral display mode can then be used to adjust the filter controls so that the instrument is only measuring the required signal.

The model 7310 is very easy to use. All instrument controls are adjusted using soft-touch, front panel push-buttons, with the present settings and measured outputs being displayed on the centrally located, cold fluorescent backlit dot-matrix LCD. Numeric outputs are shown in volts or amps rms or in decibels with respect to a preset reference level and maximum and minimum level indicators indicate the highest and lowest amplitudes since the last reset operation. A large-digits display mode is particularly convenient when using the instrument for a single type of test, giving a very easy to read display.

A LabVIEW driver, downloadable from this site, supports all instrument functions.

Capable of measuring signals from DC to 60 kHz, the instrument is ideal for many audio, mechanical, vibrational and electronic measurements.

Measurement Modes
	AC RMS voltage or current
	AC RMS voltage or current with respect to preset 0dB level
	Average DC voltage or current
	Average DC voltage or current with respect to preset 0dB level
	Minimum signal since last reset operation
	Maximum signal since last reset operation
Displays		Cold fluorescent backlit 64 ´ 240 pixel dot-matrix LCD with the following displays:
	Main Display	Principal instrument controls and digital and analog bar-graph displays of measured signals
	Spectral Display	Spectral density of input signal over selected frequency range with a linear or logarithmic power scale
	Large Digits Display	One selected instrument output shown in large digital format
	Graphical Display	Display of one or two selected instrument outputs, or auxiliary inputs, as a function of time
	Other Menus	Menu system with dynamic key function allocation allowing access to all instrument controls. On-screen context sensitive help.
Signal Channel
	Voltage Inputs
	Modes	A only, B only or Differential (A-B)
	Full-scale Sensitivity Range	AC measurement mode: 10 µV to 1 V rms in a 1-2-5 sequence; DC measurement mode 1 mV to 1 V in a 1-2-5 sequence
	Input Impedance	10 MW // 30 pF
	Maximum Safe Input	30 V pk-pk
	Voltage Noise	5 nV/Ö Hz at 1 kHz
	CMRR	> 100 dB at 1 kHz degrading by 6 dB/octave
	Frequency Response	AC measurement mode: 300 mHz to 60 kHz
	Gain Accuracy	0.2 % typ, 0.6% max.(full bandwidth)
	Distortion	-90 dB THD (60 dB signal channel gain, 1 kHz
	Grounding	BNC shields can be grounded or floated via 1 kW to ground
	Current Inputs
	Full-scale Sensitivity	10 pA to 1 µA in a 1-2-5 sequence
	Input Impedance	< 250 W at 1 kHz
	Maximum Safe Input	30 V pk-pk
	Voltage Noise	130 fA/Ö Hz at 1 kHz
	Frequency Response	AC measurement mode: 300 mHz to 60 kHz
	Gain Accuracy	£ 0.6 % typ
	Grounding	BNC shields can be grounded or floated via 1 kW to ground
Line Filter
	Type	Two cascaded analog second-order frequency rejection (notch) stages, set to center frequencies equal to the line frequency (F) and twice the line frequency respectively
	Settings	F, 2F, F&2F or disabled
	Frequency Rejection	Each stage gives greater than 34 dB attenuation at ±2 % of center frequency
Main ADC
	Type	18 bit ADC
	Sampling Rate	200 kHz
Digital Filter
	Type	Two cascaded second order digital filter stages giving an overall fourth-order response.
	Settings	Bandpass, Low-pass or Flat
	Controls
	Bandpass	Center Frequency: 1.000 Hz to 60 kHz; Q-factor: 2 to 100 in a 1-2-5 sequence
	Low-pass	-3dB Frequency: 10 Hz to 28 kHz
	Flat	None
True RMS - DC Converter & Output Processor
	Description	True RMS algorithm implemented using a DSP running at a 200 kHz sampling rate and managed by a powerful 68000-series host processor
	Output Zero Stability	Digital Outputs: No zero drift on all settings; Displays: No zero drift on all settings: Analog Outputs: < 5 ppm/ºC
	Output Smoothing	Time Constant: 5 ms to 10 s in a 1-2-5 sequence; Slope: 6 or 12 dB/octave
	Offset	Auto and Manual offset of up to ±100 % of the full-scale sensitivity range applied prior to the RMS-DC conversion
Auxiliary Inputs
	ADC 1 and 2
	Maximum Input	±10 V
	Resolution	1 mV
	Accuracy	±25 mV at full-scale
	Input Impedance	1 MW // 30 pF
	Sample Rate	ADC 1 only: 40 kHz max; ADC 1 and 2: 13 kHz max
	Trigger Mode	Internal, External or burst
	Trigger input	TTL compatible
Outputs
	Signal Monitor
	Amplitude	±10 V FS
	Impedance	1 kW
	Filter Output
	Function	Representation of input signal after filtering by digital filter stage
	Amplitude	±10 V (100% = ± 5.0 V in bandpass mode)
	Update Rate	200 kHz
	Output Bandwidth (-3dB)	25 kHz
	Output Impedance	1 kW
	DC Output
	Function	OUTPUT, dB OUTPUT, RATIO, LOG RATIO or USER EQUATION
	Amplitude	±10 V full scale
	Impedance	1 kW
	Update Rate	200 Hz
	Auxiliary D/A Output 1, 2, 3 & 4
	Max Output	±10 V
	Resolution	1 mV
	Impedance	1 kW
	8-bit Digital Output	8 TTL compatible lines that can be independently set high or low to activate external equipment
	Power - Low Voltage	±15 V at 100 mA rear panel DIN connector for powering SIGNAL RECOVERY preamplifiers
Data Storage
	Data Buffer
	Size	32k 16 and 32-bit data points, may be organized as 1´ 32k, 2´ 16k, 3´ 10.6k, 4´ 8k, etc.
	Max Storage Rate	From NRV: up to 800 16-bit values per second; From ADC1: up to 40,000 16-bit values per second
Interfaces		RS232, IEEE-488. A second RS232 port is provided to allow "daisy-chain" connection and control of up to 16 units from a single RS232 computer port.
Power Requirements
	Voltage	110/120/220/240 VAC
	Frequency	50/60 Hz
	Power	< 40 VA
Dimensions
	Width	350 mm (13.75")
	Depth	415 mm (16.5 ")
	Height
	with feet	105 mm (4.1 ")
	without feet	91 mm (3.6 ")
Weight		8.1 kg (18 lbs)

SIGNAL RECOVERY is part of Advanced Measurement Technology, Inc, a division of AMETEK, Inc.
It includes the businesses formerly trading as EG&G Instruments (Signal Recovery),
EG&G Signal Recovery and PerkinElmer Instruments (Signal Recovery)

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