Digitimer NeuroLog NL822 User Manual

Users Manual
Multi-Channel, AC coupled, Miniature Low Noise Amplifiers

Introduction

The NL820A ISOLATOR is the module at the heart of the NeuroLog™ System Isolated Amplifier range of
components that meet, or exceed, the BS5724 and IEC601-1 patient leakage specifications.
The NL822 and NL824 miniature, low-noise, AC coupled (or NL832/834 DC) pre-amplifiers complete the
system.

General Description

NL822
x100
MUTE
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x10K
10Hz
CAL
3Hz
30Hz
1
COM
Digitimer Ltd
The NL822 and NL824 units are low noise differential AC pre-amplifiers with simple three step control of gain
and low frequency cut-off point. High frequency response extends to 30kHz and no control of cut-off point is
provided. The designs provide high common mode rejection of signals from DC to frequencies in excess of
1kHz.
The NL822 AC Pre-Amplifier provides two differential amplifier channels with a common terminal and a
built-in 100 microvolt calibration signal.
The NL824 AC Pre-Amplifier has four differential amplifier channels referenced to a common terminal with
100 microvolt calibration facility.
Both units have a mute facility for suppression or reduction of overload artefact signals. This can either be
operated by a push button on the front panel or, when used with the NL820A ISOLATOR, triggered from an
electrical signal to provide an automatic mute feature.
Power supply to either unit will normally be provided by an isolated supply system within the NeuroLog
NL820A ISOLATOR module from supply rails of +13 volts nominal. A 9-way plug fitted to a three metre length
of cable provides for supplies, channel outputs and remote mute control.

Stand-alone use

The NL822 and NL824 will operate from DC supplies in the range +10V to +15V but it must be remembered
that the unit will not isolate the signals unless a specific isolation stage is used.
Digitimer Ltd
E-mail: sales@digitimer.com
NeuroLog™ System
NL822 - 2-Channel AC Pre-Amplifier
NL824 - 4-Channel AC Pre-Amplifier
x100
x1K
x10K
10Hz
3Hz
30Hz
2
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Tel:+44 (0)1707 328347; Fax:...373153
NL824
x100
MUTE
x1K
x10K
10Hz
CAL
3Hz
30Hz
1 COM 2
Digitimer Ltd
Website: www.digitimer.com
NL822/824
x100
x1K
x10K
10Hz
3Hz
30Hz
COM 4
3
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