For EMG, EEG, ECG, ERG, Evoked response, Skin Conductance, Tremor Measurement, Auditory Brainstem and many more life science and engineering research applications
The 1902 is a versatile modular unit designed to work with modern computer-controlled data acquisition systems. Developed for a broad range of applications, the 1902 accepts biological and instrumentation signals from a wide variety of sources.
It is available in single or multi channel configurations. Communication with the computer is achieved through a serial line, allowing multiple sets of units to be controlled simultaneously.
Software controllable features
Programmable gain with readback
Selectable high and low pass filter settings
Dynamically controlled 12-bit offset
Selectable mains notch filter
AC/DC coupling
Optional input clamping
A major advantage of programmable amplifiers is the degree of interaction between the signal conditioner and the application software recording the data. The 1902 is directly controlled through the CED data acquisition and analysis programs Spike2 and Signal, or through a stand-alone control application.
The isolated electrode input
The 1902 is designed to a specification worked out in conjunction with major UK physiological laboratories for an isolated amplifier to comply with EN 60601-1. It provides a low noise differential electrode input developed specifically for EEG, EMG, ECG and evoked potential applications.
IMPORTANT NOTE: The 1902 is research equipment and is not sold as a medical device within the meaning of the European Medical Devices Directive.The transducer input port (non-isolated)
The transducer input port is suitable for use with a wide range of bridge and other transducers. It will accept single-ended and differential inputs and provides 5 volt and 12 volt outputs to supply the excitation voltages required by many transducers. Applications include: isometric force, strain gauges, temperature, pressure, acceleration, displacement and goniometers.
The 1902 is available in a transducer-only form with no isolated electrode input.
Standard features
Digital filters generated according to user-entered filter cut off values
Trigger input converter from high-level pulses or switch closures to 5V TTL
Overload indicators with software readback
EMG filter with full wave rectifier and programmable post-filter gain
16-bit ADC for digitisation of transducer and other low-bandwidth signals and transmission of results down the serial line
Specialist 1902 options
Stimulus artefact clamp to avoid saturation of the amplifier when using high intensity magnetic or other stimuli
Buffer option: maintains common-mode rejection when a single reference electrode needs to feed multiple channel inputs
ECG front end with 5 lead switching under software control. Lead configurations available: I, II, III, aVL, aVR, aVF and V. Calibrator: 1 mV rectangle wave. Gain is selectable from x100 to x100,000
CED 2502 skin conductance expansion module takes direct measurements of conductance (GSR) using the constant DC potential method
Applications 1902s are suitable for direct connection to the subject to record a variety of biological signals including EEG, EMG and ECG. With an additional module, they can also be configured to measure skin conductance. The non-isolated transducer input allows connection to many types of transducers for capture of other data such as force, temperature, acceleration, strain and displacement.
Both Spike2 and Signal software packages include built-in control for the 1902. Each package interacts with the 1902s to automatically adjust scaling and add markers to annotate changes in amplifier settings where appropriate. Amplifier settings are stored in Spike2 and Signal sampling configurations, therefore when switching between experiments, amplifier settings are restored automatically.
1902 and Spike2
Spike2 records event and waveform data into a file with a continuous time base, making it ideal for applications including sleep studies, biomechanics, behavioural experiments and cardiovascular research. Changes to the 1902 gain and other software controlled settings are recorded as text notes alongside the conditioned waveforms.
With the aid of active cursors, you can take measurements automatically while recording the amplified and filtered signals. Features from waveforms such as ECG and blood pressure can be detected, and their times, values and other measurement results plotted to an XY view for display and export in spreadsheet format. Results can also be saved inside the data document as additional channels, marking where the measurement was taken and the result.
1902 and Signal
Signal, being a frame-based recording system, is more suited to applications such as evoked response (visual, auditory, electrical, TMS). It is also ideal for biomechanical applications, for example in conjunction with force plates.
For TMS and electrical stimulation experiments, the 1902 optional input clamp is designed to suppress artefacts which would otherwise saturate the amplifier if the recording site is close to the stimulation point.
Main amplifier
Isolation pre-amplifier
BandwidthDC to 10 kHz (-3dB) in DC mode 0.16 Hz to 10 kHz in AC mode
Gain accuracy±2%
Front end type
Low noise EEG
ECG
Input impedance
10 GOhm
Filter responseBessel or Butterworth
Filter slope (low- and high-pass)2nd or 3rd order (12 or 18 dB/octave)
