VooDoo DCR 6000, Planning & Installation Manual

Page: 36 / 149

1. General DCR 6024/6128/6000
1 – 27 Planning and Installation – Rev. 1 / 7. 2001
Motor Control Unit MCU
All commands and messages to the MCU are passed via a Dual Port Ram. MCU
controls the threading logic clock generator and the servo system DMC. Sensor
information and control signals to the threading logic are passed via an 8 bit parallel
bus. The tape threading motors are controlled via pulse width modulated signals.
MCU monitors permanently all sensors and tacho generators during tape travel.
All ballistic functions of the Tapedeck are defined by this unit.
Digital Motor Control DMC
This unit is a feedback control system which controls capstan, scanner and winding
motors. Six feedback systems are controlled simultaneously (headwheel velocity,
headwheel phase, capstan velocity, capstan phase, left and right tape tension).Ta-
cho information of all motors, control track and analog output of tape tension arms
are passed to this unit. Motor power amplifiers are interfaced via analog output
stages.
Clock Generator
All basic reference clocks which are used by the servo and control system are gen-
erated in this unit. It includes also the control track signal generator. All clocks are
derived from a frame pulse and a high frequency clock which are delivered by the
signal Processor. If no external clock is present the pulse generator will be switched
to an internal oscillator automatically. The head switch pulse generator works with
clocks derived from a PLL circuit which is locked to the scanner tacho. If the scan-
ner is not running the head switch pulse generator will be switched to the reference
clock.
RF & Sensor Evaluation
The RF-evaluation circuit converts the analog signals from the tension arms, the
position sensors of the Tapedeck and the RF-envelope signals to a digital value.
Sampling and conversion of the RF-envelope is done with respect to the scanner
phase. Special software filter algorithms are applied to the conversion process.