Timecode Generator - possible?

S

shoei600

New Member
SMPTE Timecode Generator - possible?

Hello very helpful forum members again,

I have a Leitch broadcast studio clock (ADC-5012) and would very much like a timecode generator for it, but they are very expensive to buy and frankly overkill for one clock. I have no problem using a GPS receiver to get accurate time and could parse this through the Picaxe but I have no idea how to go about the timecode generation in both hardware and code (or indeed if this is possible with Picaxe).

I would welcome the thoughts of the far more knowledgeable chaps on this forum that make it the joy that it is. This could be a non starter.

The datasheet for the clock can be found here: http://catalogs.infocommiq.com/AVCat/images/documents/pdfs/ADC-5100_Series.pdf. It will take either EBU or SMPTE timecode.

Many thanks,

James.
 
Last edited:
hippy

hippy

Ex-Staff (retired)
It's been a long time since I did any SMPTE time code stuff, and then it was only reading it.

I recall there's 80 bits per frame and with frames at up to 30 FPS, that's 2400 BPS which should be possible to handle with a PICAXE. The actual rate depends upon how many FPS. It is self-clocking so bi-phase / Manchester encoded so that doubles the transition rate but should still be possible to handle and the bi-phasing could be handled in hardware to lighten the load on the PICAXE.

The tricky part might perhaps be getting the data ready to put out while putting it out. The data is BCD and I recall various parity bits need calculating.

I would say it is possible, but to be broadcast standard would require some serious effort. The cost in broadcast equipment is in having everything sub-microsecond accurate over long periods of time.

I guess results would depends on what the timecode generated is to be used for. If it's just to drive the clock then I reckon it's possible. The bit rate streamed doesn't have to be accurate and you likely just need the second ticks to fall fairly accurately. You may not even have to generate data other than once a second.
 
JimPerry

JimPerry

Senior Member
When no source of time code is available, the ADC may be configured as a
time code generator, using its internal quartz crystal. An internal cable
change is all that is required. The secondary reference must be set to
internal, and the time code format DIP Switch must select either SMPTE or
EBU format.
When used as a generator, the ADC can drive multiple high
impedance, time-code-reading devices.
Click to expand...
Use your clock as signal source :confused:
 
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