User manual ALESIS AI2

[. . . ] ALESIS AI-2 Reference Manual TABLE OF CONTENTS CHAPTER 1: INTRODUCTION 1. 0 ABOUT AI-2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. 1 IMPORTANT NOTES ABOUT THIS MANUAL . . . . . . . . . . . . . . . . . . . . . . . 3 1. 2 OVERVIEW OF MAIN FUNCTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. 2A Multiple Control Methods. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . [. . . ] If no controller is detected then the AI-2 switches to time code chase mode and the reference is set to reader in. The default code rate and type is determined by configuration dip switch one, if off, to 38 29. 97 Hz/30 and if on, to 25 Hz/25. This however automatically switches if a different code type is detected at the reader input. The digital audio sample rate at the AI-2's word clock outputs is always set to the ADAT's standard operating frequency of 48. 000 KHz 5. 8 LONGITUDINAL TIME CODE (LTC) The AI-2 has a longitudinal time code generator which is used to supply the BRC and other external devices with LTC. The AI-2 takes the ADAT time code on tape and converts it to either SMPTE or EBU time code. The AI-2 time code generator is not intended to be a generator in the traditional sense but a simulation of a normal analog tape, time code output. The time code generated is not ADAT absolute time, as shown on the ADAT front panel, but a virtual or relative time code, that is ADAT tape time minus the AI-2 offset. For example, if the ADAT time is 30 minutes and the offset is minus 1 hour then the AI-2 time code output would be 1 hour, 30 minutes, calculated as follows: (00:30:00:00) - (-1:00:00:00) = (01:30:00:00) From this calculation, it should be noted that the negative one hour offset gives a positive time code output. If the offset is positive then the calculation would be as follows: (00:30:00:00) - (1:00:00:00) = (23:30:00:00) In this example the time code calculation wraps around the 24 hour boundary and the time code output will be 23 hours and 30 minutes. The AI-2 time code output can be selected to generate when the ADAT is in play only or when it is in play and wind modes. The code in fast forward and rewind is generated in play speed bursts, with frame numbers dropped out so that it keeps up with the tape position. The AI-2 also generates continuous VITC style time code when the transport is in stop. The generator mode and still options are selectable in the reference setup menu. 39 TIME CODE ALESIS AI-2 REFERENCE ALESIS CORPORATION, LOS ANGELES CONTROL MIDI VID IN EDITOR LYNX-2 / MICRO LYNX IN OUT IN MIDI OUT BRC THRU GEN OUT W/C OUT ADAT SYNC OUT S/N POWER CONFIG RDR IN W/C IN MANUFACTURED BY TimeLine Vista, Inc. MADE IN USA CAUTION: TO PREVENT ELECTRICAL SHOCK DO NOT REMOVE COVERS. REFER SERVICING TO QUALIFIED SERVICE PERSONNEL. THIS DEVICE COMPLIES WITH PART 15 OF THE FCC RULES. OPERATION IS SUBJECT TO THE FOLLOWING TWO CONDITIONS: (1) THIS DEVICE MAY NOT CAUSE HARMFUL INTERFERENCE, AND (2) THIS DEVICE MUST ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING INTERFERENCE THAT MAY CAUSE UNDESIRED OPTERATIONS. AI2014A MIDI TIME CODE LONGITUDINAL TIME CODE 5. 9 MIDI TIME CODE (MTC) The AI-2 generates MIDI Time Code which is available at the MIDI OUT connector in the control section of the AI-2 rear panel. Operation of the MIDI time code generator follows the LTC generator mode, if the LTC generator is set to generate code in still, play and wind then the MTC generator will do the same. The MTC output always matches the time code at the GEN OUT connector, which as described above, generates a virtual or relative position for the ADAT at any given time. The MTC generator can be turned on or off in the MIDI setup menu. It should be noted, that the LTC must be on for the AI-2 to generate MTC. When the MIDI connectors in the control section are being used for MIDI machine control, or for controlling the BRC, the precise timing of the MIDI Time Code output cannot be guaranteed, however every effort has been made to maintain the integrity of the MTC transmission. 5. 10 TIME CODE AND SAMPLE CLOCKS Any device which combines both time code and digital audio sample clocks, must maintain a very accurate interrelationship between the time code rate and the sample clock rate for the system to synchronize. The AI-2 generates both time code and digital audio sample clocks with an extremely precise and consistent relationship. [. . . ] Example: To describe a time code format as 30 NDF is to say that the frame rate is 30 fps and the code type is non-drop frame. Simply saying either 30 or drop frame defines only part of the SMPTE time code. A special signal generator designed to generate and transmit SMPTE time code at one of the international formats and rates. A counter designed to read and display SMPTE time code. [. . . ]