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BioSigRP Tech Notes

Running example files crashes BioSigRP

TN0921

Product: BioSigRP
Version: 76
Date Added: 2013-05-20

Issue

BioSigRP stops responding when running example files. Observed on Windows XP and Windows 7.

Solution

TDT recommends updating to BioSigRP v100 (Downloads Page).

BioSigRP v76 crashes when opening older .awf files

TN0920

Product: BioSigRP
Version: 76
Date Added: 2013-05-20

Issue

BioSigRP v76 crashes when opening v74 .awf files.

Solution

To resolve all file compatibility issues, TDT recommends installing BioSigRP v100 or greater Downloads Page. It is a standalone package and no longer requires prerequisite installation of TDTDrivers and SigGenRP packages. It is NOT compatible with any files generated by v76 release, but it does include a file conversion tool, available in the C:\TDT\SigGenRP\BioSigRP\Convert folder.

Using an RX and RA16PA for ABR acquisition in BioSigRP

TN0840

Product: BioSigRP
Version: All
Date Added: 2008-12-01

Issue

When using a Medusa preamplifier (RA16PA, RA16SD, RA4PA, or RA4SD) with an RX device for acquisition in BioSigRP, there are several issues that should be addressed.

Voltage Scaling and Artifact Rejection

BioSigRP sets its input voltage range according to the acquisition device. For RX devices this is ± 10 V. However, the voltage range of the Medusa preamplifier is ±4 mV. This discrepancy between the actual and expected input voltage range renders the BioSigRP artifact rejection feature ineffective. The smallest artifact detectable in BioSigRP would be 1% of 10 V or 100 mV. This is well outside the possible range of values that can be acquired from the Medusa preamplifier.

Digital Control Bits are not Automatically Configured

The digital I/O on RX devices are programmable as either inputs or outputs and must be configured accordingly before they can be used with BioSigRP.

Specific RX Device Overhead Delays

When acquiring digitized signals from a Medusa preamplifier, additional overhead delays appear on RX devices. These delays are slightly longer than those present on RP devices such as the RA16BA Medusa Base Station.

Note on Delays

Overhead delays as well as any DAC and ADC delays are unaccounted for but will not affect recordings, especially at higher sampling rates.

Workaround

An RX compatible circuit has been provided which corrects the voltage scaling, artifact rejection, and digital control bit issues. The circuit can be downloaded here.

To use the new circuit file in BioSigRP:

  1. Extract the contents of the zip file.

  2. Open the RX_ABR_ACQ folder.

  3. Read and follow the directions in the Readme.txt file.

  4. Run BioSigRP.

  5. Configure the acquisition device by loading the newly added circuit file Record25Kx2(RX).rco as the intended Acquire RCO in the BioSigRP Acquisition Setup dialog box.

Solution

When using the Medusa preamplifier for acquisition in BioSigRP, the RA16BA Medusa Base Station can be used to avoid issues related to voltage scaling and artifact rejection.

BioSigRP cursors not exported correctly from the worksheet

TN0834

Product: BioSigRP
Version: 4.4.1
Date Added: 2008-07-30

Issue

When exporting a filtered data set from the worksheet, the original cursors from the unfiltered data set are exported instead of the new cursor positions.

Solution

Upgrade to a version of BioSigRP released ⅓/11 or later.

Running SigGenRP or BioSigRP causes AP2 Driver Failure error

TN0832

Product: SigGenRP, BioSigRP
Version: All
Date Added: 2008-07-11

Issue

When BioSigRP and SigGenRP are installed on the PC, uninstalling one will cause the remaining application to fail. The following error is displayed:

Solution

Reinstall the affected application to fix this issue.

DAC and ADC delays not accounted for correctly in BioSigRP

TN0221

Product: BioSigRP
Version: All
Date Added: 2006-09-22

Issue

Devices such as the RP2, RX6 and RX8 uses Sigma-Delta D/A and A/D to ensure high quality signal conversion. However, the high bandwidth low distortion characteristics associated with Sigma-Delta converters comes at the cost of DAC and ADC delays. These delays must be accounted for to ensure accurate timing of stimulus and recording. Currently, BioSigRP automatically detects the hardware and, if the device is an RP2.1, corrects for these delays. However, BioSigRP also applies the RP2.1 known delay information to the RP2 and does not auto- correct for any other devices.

Workaround

For the RP2, since the incorrect delay is implemented (longer than required), delay your SigGen signal by one millisecond by modifying the start time of your signal segments. For example, if your signal contains one segment, set the start time of the segment to 1 msec. For consistency, also increase the length of the signal by 1 millisecond.

For other devices, Use the table below to find the delay associated with your device, then use the TTLDelay2 component in your circuit to implements delays based on a user-defined number of samples.

Device DAC Delay ADC Delay
RP2.1 30 samples 65 samples
RA16BA 18 samples NA
RM1/RM2 17 samples 16 samples
RX6 43 samples 70 samples
RX8 23 samples 47 samples
Recorded signals appear noisy when using 100 kHz sample rate in BioSigRP

TN0200

Product: BioSigRP
Version: All
Date Added: 2005-11-07

Issue

When using the continuous 100 kHz sample rate RCO (ConRec100Kx1.rco), the recorded signal appears to be very noisy.

Workaround

The noise associated with the continuous 100 kHz sample rate RCO file is related to high cycle usage. There are four workarounds:

  1. Use this RCO circuit which reduces cycle usage but will not drop the first 4 averages.

  2. Continue to use the continuous 100 kHz sample rate but leave the MultiView plot (top center) on the stimulus view. The recorded signal will only appear noisy when viewing the other plots (Raw A/D Input, Freq etc).

  3. Switch to a lower sample rate, such as 50 kHz, if possible.

  4. Consider upgrading to a high-performance multiprocessor such as the RZ6. These devices are not constrained by cycle usage limitations at 100 kHz or 200 kHz.

'SigGen Engine Error emess' error message

TN0169

Product: BioSigRP
Version: All
Date Added: 2005-03-07

Issue

While using BioSigRP a "SigGen Engine Error emess" is displayed. This message is related to a memory management problem during loading and does not affect data collection.

Workaround

Click OK to continue. Data collection will be accurate.

'Record file nearly full. Consider specifying a new record file.' warning

TN0161

Product: BioSigRP
Version: All
Date Added: 2004-12-29

Issue

If the size of a history file reaches its maximum, a "Record file nearly full. Consider specifying a new record file." warning will appear. This message might be displayed while the system is running or when a history file is loaded. The allowable size of a history record file (.arf) is about 30MB.

Workaround

If the message is displayed while you are recording data, you will need to stop acquisition and select another .arf to save the remaining data. If opening files for analysis purposes, the best solution is to try to access as few files as possible and access one file only once (load all records possibly to be used). If it is necessary to access many files, then quitting and restarting BioSigRP will force the open files to close.

Noise peaks appear at regular intervals in BioSigRP recordings

TN0160

Product: BioSigRP
Version: All
Date Added: 2004-12-29

Issue

Noise peaks that occur at regular intervals can occur when the system is affected by 60 Hz electrical noise. You might not see the peak at 60 Hz if you have a 60 Hz notch filter in place, but harmonics can still be present.

Solution

There are three things you can do to minimize BioSigRP recording problems related to electrical noise:

  1. Record in an environment where the 60 Hz noise is limited (like a Faraday cage).

  2. Ensure that the electrode impedances are as close together as possible. If you are using a 2 kOhm electrode and a 4 kOhm electrode, you will only get a reduction in the 60 Hz noise and its multiples by half (as opposed to virtually eliminating it in the amplifier). A differential amplifier will eliminate signals that are common to both the recording and reference electrodes. If the impedances to these electrodes are different, the common signals will have different voltages and not be subtracted out.

  3. Set the stimulus presentation rate at something other than a multiple of 60 Hz. For example, if the presentation rate were 20 Hz, then it would line up perfectly on the 60 Hz noise, and the noise would not be averaged out. Instead, make the stimulus presentation rate something like 21 Hz (or 11 Hz, if you wanted to use a 10 Hz presentation rate).

BioSigRP freezes or displays a flat line in the multi-plot during averaging

TN0126

Product: BioSigRP
Version: All
Date Added: 2004-05-04

Issue

BioSigRP might freeze or display a flat line in the Running Average or EEG plot during averaging, if:

  1. The preamp is not connected and turned on.

  2. The stimulus or acquisition circuit (RCO file) is not compatible with the selected device.

  3. The configuration file is damaged or corrupted.

  4. Channel 2 circuit components are erroneously being read and preventing the SGI from completing.

  5. Length of sound output sig file for Channel 1 does not match length of Channel 2 file.

Solution

The stimulus or acquisition circuit (RCO file) is not compatible with the selected device:

Problems will occur if the sampling rate and/or the number of analog I/O ports accessed in the RCO does not match the acceptable sampling rate or number of analog I/O ports for the device. For example, the Record25KX4.rco includes four channels of acquisition and the RP2.1 has only two analog inputs. Also, the Record50KX2.rco uses a sampling rate of 50K and the RA16 accepts a maximum sample rate of 25K on the A/D inputs.

The configuration file is damaged or corrupted:

The configuration file can be damaged or corrupted anytime BioSigRP crashes. Using a damaged file can cause a variety of problems and might cause the software to crash. Recreating and using a new, but identical, configuration file can eliminate the problem. If this solves your problem be sure to delete the corrupted or damaged configuration file.

Scale control shortcut keys are reversed in the Running average plot

TN0106

Product: BioSigRP
Version: All
Date Added: 2004-02-05

Issue

When viewing the running average in the multi-purpose plot, the shortcut keys for the Expand and Reduce scale features are reversed. Pressing "+" on the numeric keypad reduces the plot scale, while pressing "-" on the numeric keypad expands the scale.

Gain setting ignored when averaging

TN0101

Product: BioSigRP
Version: Version number < 4.42
Date Added: 2003-08-07

Issue

Setting a Zero Onset value in the Timing section of the Acquisition Setup will cause the Gain setting to be ignored when averaging.

Workaround

If possible, use an Onset Delay instead of a Zero Onset. If Zero Onset is used, rescale the signal in the worksheet using the Scale function.