Tascam MMR-8 - Manual (Page 30)

30 TASCAM MMR-8 User’s Guide • Chapter 2 • Installation MMR-8
Biphase Connections
Biphase is a control signal typically generated by a film projector and is traditionally used to interlock the
operation of the film with sprocketed magnetic tape machines. The Biphase Operations Board (BOB) on
the back panel of the MMR has four biphase input connections and one biphase throughput connection for
synchronizing the operation of the MMR-8 to film transports. Use Setup Menu 100, Sync Group, to select
which of the four Biphase inputs (Sync Groups) will control the system. The biphase connections use
6-pin modular RJ-12 connectors (like those used on commercial phone systems) and twisted multi-pair
cabling (Category 5 Ethernet). Up to 100 feet of cable can be typically run from a biphase device to the
MMR-8 or vice versa. The pinout diagram for these connectors is given in Appendix D: Cable
Information.
Unlike time code, Biphase gives only speed and direction and does not contain an absolute
address. To set the MMR to lock to biphase, use Setup Menu 000, Control Mode. The various
biphase parameters such as frame rate, pulse rate, acceleration, etc. are set in the 300 series Setup Menus.
Not intended for public telecommunication network connection.
Digital Audio Sample Reference Connections
In combination with a frame reference for video and film, there may also be a sample reference for the
audio. The sample reference can be taken from one of the digital inputs, the frame reference, the Word
Clock input (if there is an active signal on that input), or the system’s internal clock source. These
connections are described here in more detail.
Word Clock
Word Clock is a digital reference signal used by many digital editors and digital tape machines. This
permits two digital audio devices to synchronize their sample clocks to facilitate digital audio transfers
between machines, and to insure that they are running at precisely the same sample frequency. The signal
is transmitted on an unbalanced coaxial cable that terminates into a BNC connector at the MMR-8 end.
The MMR-8 has both a digital WORD CLOCK IN and a digital WORD CLOCK OUT connection using
BNC connectors.
When an external tape machine is to control the sample rate of the MMR-8, connect the Word Clock
output from that machine to the WORD CLOCK IN on the MMR-8. When the MMR-8 is to control the
sample rate of an external machine connect the WORD CLOCK OUT from the MMR-8 to the Word
Clock In on the controlled machine. The maximum practical cable distance is up to 100 feet. Use setup
menu 002 to select the sample reference for the MMR-8 system. Normally this is a 48 kHz TTL-
compatible (5 volt) signal.
AES/EBU Sample Rate
When using AES digital audio input, the audio sample reference for the MMR-8 can be taken from one of
the four AES digital inputs. Use setup menu 002 to select the sample reference for the MMR-8 system.
Setup Menu 600 selects which AES/EBU digital input pair will be used for the reference signal (input
1+2, 3+4, 5+6, or 7+8).