Source/subsource code for bubblephone

[WayneCrawford]

We have added a 'bubblephone' channel to some of our ocean bottom seismometers. This consists of electronics that bandpass the hydrophone data at a high frequency and then outputs the envelope at a low-enough frequency for the datalogger to correctly sample. This RSAM-like technique allows the instrument to record "bubbles" (several kHz) even though it only samples 125x/second.

Previously we would have given a source code of 'X' as it is derived data, even though not derived by a computer. I imagine we should instead give it a source code of 'D' (pressure) and request a new sub-source code ('B' for 'bubblephone', 'R' for RSAM?...). Do you agree and, if so, how should I request this from FDSN. The proposed documentation doesn't say this.

Regards
Wayne