|
 TECHNICAL TIP OF THE DAY
Patching External DC Coupled Signals Directly into Cheetah
32 and Cheetah 160 Systems
by: Casey
Stengel
Many experiment setups need analog
behavioral signals from photocells, joysticks, strain gages, stimulator
outputs, etc. to be recorded with the neural signals. Two methods
are used to record these signals depending on the amplitude of the signal
and if the DC component is important. The distinction of the method
used is based on the design of the Lynx-8 amplifier, in which all
channels are AC coupled.
AC coupled signals less than 100 millivolts may be patched directly into
the ERP-27 CSC channels and will be acquired thru the Lynx-8
amplifier. For signals larger than 100mv a Lynx-8 input gain jumper
may be adjusted to accommodate signals up to 10 volts. Cheetah software
will acquire the signals as normal.
For DC Coupled Signals, with larger
amplitudes of 0.5v to 10v, requires the signal to be directly connected
to the A/D inputs, without the AC coupling of the Lynx-8 amplifier.
If your Cheetah32/160 system has a unused bank of 8 A/D inputs the
L8-FBNC cable is used to connect upto 8 BNC signals directly into the
bank of 8 A/D inputs. If your system does not have a free A/D input
bank of 8 channels (but you can spare a channel or two) then a pair of cables
is inserted between a Lynx-8 amplifier Output Connector and the Analog
A/D input cable/connector. To make this connection two cables, the
L8-BNC and L8-FBNC, can be used to connect up to 8 channels. These
two cables are inserted between the amplifier output and the A/D input
connector because these will create a MDR-36 male to female cable with 8
BNC connections that may be "tapped into" for connections of
the DC signals. Note that the respective Lynx-8 channel(s) will be
disconnected and unusable as the A/D input is now being used for the DC
signal.
|
