5/6/97
Simple Synchronization via Dolby 501/502 or 523/524
Using Two IS-1 Units
How to think about the IS-1 Synchronizer
The Master IS-1 acts as a time code generator that sends time code and machine control (Stop/Start/Rewind, even Record if you enable it) down the serial port of the ISDN-connected Dolbys at 1200 baud. This connects to another IS-1 that is plugged into a 9-pin controlled Slave VCR or DAT machine. The timecode may be internally generated in the IS-1 and stopped and started by the machine control buttons on the front panel, or it may be jammed from timecode from a local controller (JSK) or master deck plugged into the Input XLR on the Master IS-1 and then turned into time code to be sent down the ISDN lines.
The button pair labled MASTER allows you to select where the IS-1 timecode gets its source: either from the timecode READER Input XLR jack or from the ISDN Serial A (RS-232) data from the Dolbys.
The Master has registers to hold two offsets that account for the encode/decode delay of the Dolby audio. The first is a one way offset (typically 1 or 2 frames). The second is a two way offset that is twice the one way offset and a little more for the round trip speed of light transit through the phone lines (typically 4 or 5 frames). The offset gets added to the timecode sent to the Slave. You select which one you want by the button marked 2-WAY. The two trim buttons on either side of the 2-WAY button add or subtract a frame from the offset currently selected. (Two way offset is selected when the 2-WAY LED is lit)
The Master IS-1 is also a complete synchronizer and can control a local deck as a Slave to the timecode as well. The lower set of offset buttons grab or "MARK" the offset between the timecode master and the position of the local Slave. The adjacent trim buttons act on that local offset. Pushing both trim buttons at the same time zeros out the offset.
The IS-1 is very slick when used with another IS-1 at the far end, but that is not always the case. Fortunately, the IS-1 can function as a stand alone chase synchronizer, receiving audio timecode from any source. And if that isn't enough, the IS-1 will even sync a video slave in reverse play if the master timecode is from a source such as a film chain. It does not release to video reference in reverse but the deck will stay in position playing backwards.
Identifying the Controls in the DISPLAY area
The grey button on the far left of the IS-1 SELECTs which value you will see in the red numerical display window during operation. The choices are Master Timecode, Slave Timecode, any Offset that is programmed in between master and slave.
The second button (VITC) may be ignored.
The third button from the left (SET) switches between the generator SET mode and normal operation. You know you are in the SET mode when the three periods (decimal points) that separate
hours.minutes.seconds.frames
in the time code window goes out and the LED next to the word SET comes on. In the SET mode there will be only one period (dot or point) which acts as a cursor to show which digit you are changing with the INCrement and DECrement buttons (sixth and seventh buttons when you are in the SET mode). Move the cursor right and left with the arrow keys (fourth and fifth button). The value will be stored when you exit the SET mode.
In the SET mode you may change these three values: the Generator Reset value (SELECTed as Master), the time code User Bits (SELECTEed as Slave), and Reader timecode reset value(SELECTed as Offset). This last value would be useful when JAMming timecode generation with an offset. Jamming timecode means generationg code based on a reference such as Reader, Video, or internal crystal (Xtal.).
The forth button may be ignored for normal synchronization. it is used to enable the JAM mode of generating timecode.
The fifth button from the left turns on and off the FRAMES Display. It affects only the display. The unit always keeps track of frames even if they are not displayed.
The sixth button resets the internal timecode generator to a preset value, starting the generator upon the next push of the same button.
The Plugs on the Back
INPUT (XLR female) reads Master timecode from the Master controller or deck(s) at the controlling end of the ISDN connection.
Serial A (RS-232) connects to and from the Dolby encoder and decoder data ports at each end of the ISDN connection. Timecode, machine control commands, and tallies are carried on this port.
Serial B (RS-422) connects to the slave deck (VCR or DAT) being controlled.
Aux B (XLR female) may be used to read timecode from the slave dexk if it does not supply timecode on the nine pin D to Serial B.
Video reference (BNC) should be connected to a "house-sync" video reference generator at the both ends of the ISDN connection. The video reference is used as a reference for the internal Master timecode generator or for slave jam sync applications. For simple synchronizing of a remote deck, the Slave unit must have a video reference since the IS-1 will sync from the received timecode at the slave end and then release speed control of the slave deck to the video sync reference.
Ext. Ref (BNC) accepts a frame rate square wave (not video). Special applications only.
Setting up the IS-1
Enter the Configuration Mode by first pressing SET and then pressing the left and right arrow keys simultaneously. The IS-1 will then offer four choices of configuration groups:
Unit
Video
Serial A
Serial B
Make your choice with the arrow keys and then press both arrows simultaneously to select that choice.
You will then be offered four stored configurations (CONFIG 1 , 2, 3, 4) which you may select and/or modify. These may be thought of as presets that will remain in nonvolitile memory when the unit is turned off. The SET key will exit from the configuration mode when you have made your choice and/or modified a configuration. Think of the Config choices under UNIT as "personality selections", ie. variations on Master or Slave.
Which Config do I use?
Config 1 should be used normally for setting up as Master. Config 2 is used when you wish to Slave to timecode coming in over the ISDN/Dolby connection and is automatically selected when you push the button MASTER: ISDN. Config 3 is used when you wish to Slave to timecode applied to the XLR Input port and is automatically selected when you push the button MASTER: READER. Config 4 may be used for non-standard applications.
Example, Set UNIT Configuration Parameters:
Press SET, then both Arrow buttons
Select UNIT, press both Arrows
Select CONFI 2, then both Arrows
Scroll through Parameters by left or right Arrows, choose values for each Parameter by DEC/INC buttons.
G Std Frame rate: usually 30, film may be 24
GEn rEF Reference source: usually Video or Reader
Not Col For NTSC video use Not Colour, 4 and 8 field are for PAL
VitC-Ltc Normal, VITC Only requires VITC reader, tapes
FRZ diSP Freeze the display
USErGrSt Set user bits upon Generator Reset (G.RST button)
JAM rdr1 Jam TC Source: Jam Slave generator from reader
JAM CodE Jam type: Jam only on good code read after JAM button
Jam OFFS Jam offset enabled (offset must still be SET)
DroPO 31 number of frames before stopping JAM on no code
bUrST 06 how often to send sequential frames @ hi speed (1 to 30)
SCOdE ON continue to repeat TC frames on stopped code
SCODE 0 Offset 0 for stationary code (0, or -1 for Adams Smith)
tout 50 Timeout
GEnU-PSt Userbits source: use SET preset value
JAM Loc ?
dISPrdr1 ?
Serial A
Serial A is the RS-232 connection through the Dolby units that goes out or comes in) over the ISDN lines. For use with Dolby units, the following are appropriate settings. See the Colin Broad IS-1 Manual or call EDnet for settings for other units (CCS, Telos, APT, Comrex, etc.)
Example, Set Serial A (ISDN RS-232) Conf. Parameters:
Press SET, then both Arrow buttons
Select SErIAL A, press both Arrows
Scroll through Parameters by left or right Arrows, choose values for each Parameter by DEC/INC buttons.
baud Baud rate: 1200bAud for Dolby AC-2
NO PAr Parity: no parity for Dolby
1 STOP Stopbits: 1 STOP for Dolby
8dAtA Data bits: 8 for Dolby
OFSt1 Encode/Decode offset added to TC sent: 01 (1 frame)
OFSt2 Encode/Decode and transit offset added to TC sent: 2 x OFSt1 for local, add a frame for LA- NY= 04 (4 frames)
Snd Rdr1 Source of TC Sent: Usually Snd Rdr1 for Master, Snd S9 (9-pin is code source) for Slave
Serial B
Serial B is the RS-422 connection via 9-pin D connector out to the controlled Slave deck. This will change slightly depending on the type of machine used, but miost 9 pin controlled video machines will operate similarly to the VO-9850 or BVU-800.
Example, Set Serial B (9-pin RS-422) Conf. Parameters:
Press SET, then both Arrow buttons
Select SErIAL B, press both Arrows
Scroll through Parameters by left or right Arrows, choose values for each Parameter by DEC/INC buttons.
Machine types 0 INPUt
1 bVU800
2 VO9850
3 PU2800
4 SSL 55
5 dA-88
6 r-dAT (Select the one you need)
Code source Ser Code (9 pin serial code)
rEC OFF disable remote record; (audio 1, 2, or both alt.)
SYNC ALL Sync All/ SY O-lap/Sync END
LOFST 00 Local offset
PLAYd 07 Play delay
PAr-o 00 Park Offset
LOCATE02 Locate Speed (0=Tapeless, 02 Normal, 04 Slow)
USE LOC Use LOCATE or SHUTTLE capabilities of local deck
SHtSPd30 Shuttle Speed
tr45 05 Number of tries to sync before giving up (5 is Normal)
Conn Mid timecode phase (MID frame or StArt of frame)
Error 04 error window for sync tries
No CHASE USE CHASE/NO CHASE command in the Slave Deck
(that is, use the internal synchronizer in a deck rather than the IS-1's synchronizer (DAT machine with a built in synchronizer for example)
POSLTC get Slave position from the LTC input to the reader
BVU-950 BVH-1000/BVU-950 personality