Teac MMR-16 v4.0 - Manual (Page 116)

TASCAM MMP-16 Owner’s Manual • Chapter 7 • System Applications MMP-16 118
Chapter 7 MMP-16 System Applications
This chapter offers more detailed information for using the MMP-16 with film and video applications.
Setup Menu parameter selections, technical background information, and block diagram connections are
also covered.
Film Post Production
A standard method of synchronizing a film transport with external audio devices (like the MMP-16) is to
use the pulse-interlock signal, or as it is more commonly known today--the biphase control signal, as a
method of generating time code from the film’s movement to drive the various audio devices.
The biphase control signal consists of two 5 volt or 12-volt pulses (called phase A and phase B) that are
generated from the sprocket drive motor on the film transport. The phase relationship between the two
pulses indicates the transport direction (when phase A leads phase B by 90
°
the film is moving forward),
while the pulse frequency indicates the relative film speed (the nominal pulse rate indicates play speed,
with higher rates indicating wind speed and slower rates indicating crawl speed).
It is only through knowing exactly how many pulses are generated per frame, and then keeping track of
the total number of pulses that have been received (while subtracting pulses for when the film is moving
in reverse), that the MMP-16 can constantly translate the biphase signal into the correct feet & frames or
SMPTE/EBU time code numbers for the film frames. Since there are several “standard” biphase pulse
rates used by the various film transport manufacturers, there is no one nominal frequency of the biphase
signal for normal film play speed (pulse frequencies of 48 Hz up to 2400 Hz are used per frame). For the
MMP-16 to interpret and lock onto a biphase signal, and to generate the correct time code numbers, it
must be given the correct Setup parameters for the type of transport that it is following (Setup Menu 301).
Table 5.1 lists the biphase pulse rates the MMP-16 can lock to and some examples of the equipment for
each rate.
Biphase
Pulse Rate Biphase Play
Frequency Transport
Type Acceleration /
fast wind speed Notes
2 ppf 48 Hz DIN standard 32 / 15x Also used by Westrex
4 ppf 96 Hz Westrex 8 / 5x Alternate DIN standard
10 ppf 240 Hz MTE 8 / 5x
20 ppf 480 Hz RCA 8 / 5x
25 ppf 600 Hz RCA 8 / 5x
50 ppf 1200 Hz RCA 8 / 5x Biphase only
100 ppf 2400 Hz MTM 8 / 5x Biphase only
ppf = pulse per frame
Table 5.1 Biphase Pulse Rate Settings