Biphasic Pulse Buffer (NL512)

Biphasic Pulse Buffer (NL512)

The interface between any bipolar signal and two of the NeuroLog NL800 isolators.

  • Enables stimulation using bipolar, isolated, constant current signals
  • High input impedance
  • Four input ranges
  • Gated input
  • Allows multiple units to be connected to a single analogue source

Item# Description U.S. List Price Quantity
72-4221 NL512 Biphasic Pulse Buffer
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The NL512 Biphasic Pulse Buffer is the interface between any bipolar signal and two of the Neurolog NL800 isolators so that bipolar, isolated, constant current signals can be used for stimulation. The NL512 features a high input impedance and four input ranges to allow a number of different modules, or an external signal (such as from the A/D in a PC), to be used for the input signal. A GATE input allows multiple units to be connected to a single analogue source with each channel being digitally enabled separately. The switch, in the OFF position, disables the module.

The NL800 Isolator features no battery usage except for when a stimulus is being presented which is achieved by using an input opto-coupler. This does suffer from having a low impedance and a DC offset which is different for each unit but the NL512 removes these problems. The NL512 provides easily adjustable internal finger controls for the DC offset of each of the NL800s.

An on-board jumper allows the unit to be driven by one of four different ranges for Full Scale current output from the NL800s. These are ± 10V, ± 5 V, ± 2.5 V and ± 1 V. The 1 mm jumper system on the board allows the unit to be driven from the unit on its immediate left, if required, via the Motherboard in the NL900 Rack and Power Supply.

Specifications
IN
Input Voltage Range ± 15 V max
Full Scale Output ± 10 V; ± 5 V; ± 2.5 V or ± 1 V by on-board jumper selection
Input Impedance 1 MO
Frequency Response > 1 MHz; this will usually be limited to less than this by the NL800
Gate
Logic Levels TTL compatible
Functions ON (unit working) - TTL high (> 2.8 V or no connection)
OFF (unit disabled) - TTL low (< 0.8 V)
Input Voltage Range ± 15 V max
Input Impedance ~85 kO
Response Time < 5 µs
ON/OFF Switch This overrides the GATE input to disable the module when set to OFF
OUT
Output DC Offset for NL800 < 0.7 to > 2.3 V - Separately set for each phase
Output Voltage Range 0 to +10 V
Output Current for NL800 Up to 20 mA
Output Impedance < 10O
Rear Connections To the NL900 motherboard allow an input interconnection for IN or GATE and the module to the immediate left without the need of a front panel cable