Setup
Option
Notes
Active Channels
Single or Four Channel
In single channel mode, unused channels are shorted to ground
Sample Freq
3 kHz (1500), 6 kHz (3 kHz),
12 kHz (6 kHz), System Rate
System Rate is the processor’s rate up to 25kHz
The number in ( ) represents the frequency content that can be
acquired at the Sample Freq without aliasing.
Impedance Frq
100 Hz, 300 Hz, 500 Hz, 1 kHz
This is the probe frequency for checking the impedance of
electrodes
Highpass Filter
Off, 1 Hz, 3 Hz
‘Off’ is a 0.1 Hz filter. There is a fixed 0.3Hz high pass analog
filter on the inputs
Auto Shutdown
Never, 1 hour, 3 hours, 5 hours
After a period of inactivity, the Medusa4Z will shut itself off to
preserve power. Press Power to re-energize after Auto Shutdown.
Maximum Voltage In
+/- 10 mV
S/N (typical)
80 dB
Input Referred Noise
(μVrms)
Depends on Medusa4Z sample rate and electrode impedance
Medusa4Z Rate
Shorted
3 kOhm
10 kOhm
3 kHz
0.15
0.3
0.5
6 kHz
0.25
0.4
0.7
12 kHz
0.3
0.6
1.0
25 kHz
0.4
0.9
1.4
Sample Delay
Dependent on Medusa4Z and RZ processor sample rates
(RZ at 25 kHz)
(RZ at 12 kHz)
(RZ at 6 kHz)
Medusa4Z rate
Samples
Samples
Samples
25 kHz
24
N/A
N/A
12 kHz
42
24
N/A
6 kHz
76
42
24
3 kHz
146
76
42
Battery
Li-Poly Battery 5 Ah capacity. Single channel mode, 30 hours between charges. Four
channel mode, 24 hours between charges. 1000 cycles of charging, not removable by user.
Medusa4Z_Input
Output-1
Output-2
Output-3
Output-4
In RPvdsEx (OpenEx, Synapse)
Use the Medusa4Z_Input Macro. Set the number of desired channels.
The macro does not account for sample delays.
In BioSigRZ:
Setup
→
Acquisition
→
Setup Inputs
→
Source
→
Medusa4Z
To avoid sample delays in your data trace, you must
match acquisition rate in BioSigRZ to the Medusa4Z
hardware Sample Freq (cycle Setup
→
Sample Freq
→
cycle Option). 25 kHz in BioSigRZ will be
System Rate on Medusa4Z.
* 12kHz recommended for ABRs
Note: This software setting does not set the hardware
sampling rate.
Important
: You must use TDT Software (Drivers/RPvdsEx or BioSigRZ)
version 92 or later to use the Medusa4Z
Software Configuration
