Wednesday, 14 March 2012

Timed Start on RM-6 and SR-4

I recently developed a new synchronisation algorithm - timed start, this will be available on software after 13th March  2012. Beta versions exist on earlier software, these work to differing degrees. Here are the details

When synchronising multiple machines the time taken to lock is proportional to the
error in frames. The larger the error the longer it will take to synchronise.

In SR and RM synchronisers there are two factors that determine the initial error as
•  The time taken for the master to enter play
•  The time taken for the slave to enter play

With Linear Audio tape machines a park offset (Menu 056) is used together with Start
Advance (Menu 055) to minimise the effect of these two factors.

Non-Linear Audio and all Video machines are parked on the same position as the
master making it impossible to use park ahead. The solution is to use a timed start, this
allows all machines to play with a minimum offset. The tables below shows results with
and without timed start using chase type 1= P (Play command only).

Note: It is not possible to use the timed start algorithm on a timecode chase synchroniser!

To get the best advantage of using timed start it is important to set the Start Advance for the machine and timecode standard as follows

  1. Enable “Menu 22 Timed Start” for example set to 5 for a 10 frame delay 
  2. Select the Generator as master
  3. Select a machine as slave
  4. Note the Chase type of the Slave
  5. Change “Menu 052- chase type” of the slave to 1=P
  6. starting from stop note the Error
  7. Adjust “Menu 055 Start Advance” as required so that the slave Error is normally 0, using Stop Start repeatedly
  8. Change the Chase type of the machine to the original setting
  9. Repeat for all machines including the master
Note1: If timed start is set up incorrectly this can increase the error and increase the time taken to lock.

Note2: Check the complete system using Chase type 1=P, if there is an error on an individual machine then adjust the start advance of that machine. If all slave machines are out by the same amount then adjust the start advance on the master.

Note3: I am working on learning software at the moment so that the start advance in learnt, On current sotware only chase type 2=LP has learning implemented.