Gap Filling Feature
The microMARS Reader software always retrieves data from a pair of SD cards, which the recorder records in a pin-pong fashion: 256 samples on bank A (or 1), 256 samples on bank B or (or 2), 256 samples on bank A, and so on.
If the secondary card is missing or not being read, the microMARS will make up for the missing card by replicating the data from the other card into the gap. This way, even if one of the cards malfunctions, is defective, or has been lost, you still receive data in the end.
The replication maintains spectral content, therefore the restored data should still be usable for a number of purposes. You can look for the replication on the 256 boundaries directly, by zooming in enough to see to watch the spectrogram, and be able to see when the malfunction occurred.
You do this by:
Opening the microMARS Reader Software
Clicking “Log” in the main window
Observe that there are at least two cards plugged in (shown as drives).
Check that the reference time, set number, serial number are the same. Also check that the bank index for 1 is 1, and the bank index for 2 is 2.
Open up the .wav file.
Zoom in on the first 256 samples.
Observe samples 1-256
Next, move forward to samples 257-512
If samples 1-256 are exactly the same as samples 257-512, then the software is compensating for the defective/malfunctioning/missing card, by copying every other 256 samples to make the data look complete.
There are many potential reasons why Reader may not be able to access a card. Mechanical is one. It could also be that a card hadn't been recognized by Windows yet when you clicked Detect Cards, mixing cards from different sets by accident, or a card reader hardware/compatibility problem.
The best guard against it is to check the Log button in Reader to make sure everything is in order before proceeding with a download. Of course, you can always re-download any time as long as the card hasn't been re-formatted.