Differential Amplifier with Active Headstage

• High input impedance.
• Excellent common mode rejection [120 dB @ 60 Hz].
• High DC tolerance, high gain, low noise & bandwidth filtering.
• Small active headstage, which can be mounted in micromanipulators.
• Suitable for use with high impedance glass or metal microelectrodes.

High Input Z, High CMR:

High common mode rejection is very important in minimizing electrical interference. The high input resistance of the Differential Amplifier Series (10¹² Ω typical) ensures that the instrument's high CMR will not be degraded by differences in source impedance at the input. This is important in extracellular recording, where the difference in resistance of the recording and indifferent electrode is often large.

High DC Tolerance:
Extracellular action potentials are typically measured in microvolts but are usually accompanied by much larger DC electrode voltages. The Differential Amplifier is designed to amplify these microvolt level events with as much as ±2 V DC at the input.

High Gain, Low Noise & Bandwidth Limiting:
With gain selections at x10, x100, x1000 and x10000, even microvolt signals are sufficiently amplified for computer and recorder inputs. Noise is very low, typically 8 µV p-p at 1 Hz to 10 kHz bandwidth. Reducing the bandwidth with the low pass and high pass filters further lowers noise.

Calibration Signal:
An internal Cal signal provides a convenient check of amplifier gain and operation.