Spike Trigger (NL201)
This transducer amplifier is a DC coupled differential amplifier intended for use as a bridge amplifier or as recorder-matching amplifier.
Wide gain range, an integral power supply for bridge excitation, excellent DC stability, switchable input time constants and a wide DC input offset adjustment are some of the NL107 features. A front panel switch grounds the output for recorder baseline adjustments. The input socket mates with the Lemo 4-Pole plug (NL963, not supplied).The NL201 Spike Trigger produces separate output pulse trains for spikes which:
- Cross the Upper voltage threshold
- Cross the Lower voltage threshold
- Cross the Lower but not the Upper threshold
The NL201 Spike Trigger is an amplitude discriminator for nerve spikes and other events, with an output that shows the levels superimposed on the signal. It produces separate output pulse trains for spikes which: (a) cross the Upper voltage threshold; (b) cross the Lower voltage threshold; (c) cross the Lower but not the Upper threshold. The window height potentiometer sets the DC level of the window and the aperture potentiometer sets the separation between the two voltage thresholds of this window. Thus, slight changes in signal amplitude require adjustments of only one setting, and it is impossible to set the upper voltage threshold lower than the lower voltage threshold.
The monitor output socket provides a display of the input signal with the lower and upper levels superimposed on it to enable easy setting of the discrimination levels. There is a choice of two internally selected input voltage ranges and a front panel switch selects either positive or negative slope and level triggering. This module is essential for converting spike trains (which are analogue signals) into trains of digital pulses; these can be analyzed using other modules (such as the NL700 Log Display) or used to synchronize displays, trigger averaging, etc. An internal jumper allows the input to be AC or DC coupled.
|Input Voltage Range||± 15 V|
|Input Impedance||1 MO|
Input Time Constant
In AC Mode
|10 sec (0.02 Hz)|
|Gain||x1 to x1000 switched 1-2-5 sequence|
|DC Offset||± 1 V at input, 10-turn potentiometer adjustment|
|20 kHz (WB), 50 Hz, or 0.5 Hz (Mn)|
|CMRR||>2500; 1 at 50 Hz|
|Output Voltage Range||± 10 V|
|Output Impedance||600 O|
|Bridge Supply||Approx. 10 V for 600 O bridge|
|Note: Can be adapted to suit most strain gauge pressure transducers|