SMPTE LTC has no dependence on the tape decks you are using.
They simply carry the 'audio' as a spare track, and record or play it exactly the same as any other track.
Got ya.
All the timecode gear is external to the tape transport (unless it's fitted as an option).
The only electrical connection between the timecode equipment and any transport(deck), is the ability to push or pull the capstan servo to aid in synchronisation.
Okay I want to use the unit at the top of this page to generate LTC.
One thing to keep in mind, is that as a high-modulation analog audio signal, there is high risk of crosstalk or leakage between channels/tracks.
This is a good point for tape machine related recordings. This is starting to gel a bit more more. Though I want this to be compatible with a DAW or a tape machine it seems like it will greatly just depend on the interfacing with the go between module.
EDIT add: The raw LTC signal when it leaves the 'generator' is usually between 0 and +6dB (0.7 and 1.0V p-p) as a square wave!
RMS value of a square wave is the same as the peak to peak amplitude. I could totally imagine a +6dB square wave being pretty bleedy.
This ends up being naturally rounded and clipped by the capacitance of cabling and electronics limitations (not to mention the tapeitself), so your reader/decoder should be designed for significant signal loss and shape/peak degradation.
sooo.. make up gain? buffer? perhaps balance the signal?
It's not rocket science, but needs to be designed.
Also, consider that the nominal 2kHz stream goes well out of the audio spectrum when spooling/shuttling the tape. Hence wideband amplifiers etc, but the decoder also has to figure out how to handle these surges well over 20kHz when moving the tape.
ahh this is good. thank you.