Digitimer NeuroLog NL824 Manual del usuario - Página 2

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Users Manual
NeuroLog™ System
NL822/824
Specification
Gain
x100, x1000, x10,000 selected by 3 position toggle switch each channel separately adjustable. When used
with the NL820A module with its 1:2:5 sequence gain control the full range covered will be x100 to x50,000 in
µ
9 steps i.e. 10mV/V to 20
V/V.
Low Frequency
These amplifiers are AC coupled to remove electrode potentials and selection by 3 position toggle switch
provides 3Hz, 10Hz and 30Hz cut-off frequencies. The amplifiers will operate with dc input differential voltages
up to 200mV from the electrodes and common mode voltages in excess of 1 volt without affecting their AC
performance.
Input Impedance
100M ohms each input to common.
Common Mode
The differential inputs provide a rejection ratio greater than -80dB (10,000:1) for frequencies up to 1kHz. Note
when used with the NL820A ISOLATOR module signals present between mains ground and the NL822/824
input system are further reduced to give common mode rejection ratios greater than -120dB.
High Frequency
No adjustment of high frequency range is provided, the -3dB point is greater than 30kHz. When used with the
NL820A module the overall system response reduces, but the -3dB is still greater than 10kHz. For adjustable
bandwidth control the NL125/126 filters can be connected to the NL820A outputs.
Noise
µ
When operated with inputs short circuited, over the full 30kHz bandwidth the noise is less than 5
V RMS. The
µ
low frequency noise from 3-100Hz is less than 1.5
V peak to peak.
Deblock/Mute
Operated by manual push button or remote logic trigger control through the NL820A. May be used to inhibit
stimulus artefact effects - mute time adjustable over the range 1-10 milliseconds.
Calibrate
µ
A square wave pulse is available from a front panel socket of 100
V amplitude at approximately 160Hz.
Connection
The amplifier channel inputs are 2mm sockets coloured red and blue to indicate relationship between input and
output as follows. A positive input at the red socket will produce a positive output, a signal at the blue input will
be inverted. The common signal return socket is coded black. Where a single ended input signal is to be
amplified, then the un-used input (red or blue) socket should be linked to the common black socket.
Calibration
The 100 microvolt calibrate signal can be connected to any amplifier channel by linking from the calibrate
socket to the appropriate red or blue input socket. The other input should be connected to the COMMON
socket.
Digitimer Ltd
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Copyright © 1992-8
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