NL822 - 2-Channel AC Pre-Amplifier
NL824 - 4-Channel AC Pre-Amplifier
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
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.
Users Manual
NeuroLog™ System
NL822/824
Digitimer Ltd
Page 1 of 4
Copyright © 1992-8
E-mail:
Tel:
+44 (0)1707 328347;
Fax:
...373153
Website:
www.digitimer.com
NL824
MUTE
CAL
Digitimer Ltd
COM
10Hz
3Hz
30Hz
x100
x1K
x10K
1
2
COM
10Hz
3Hz
30Hz
x100
x1K
x10K
3
4
NL822
MUTE
CAL
COM
1
2
x100
x1K
x10K
10Hz
3Hz
30Hz
10Hz
3Hz
30Hz
x100
x1K
x10K
Digitimer Ltd
