Section Il. DETAILED FUNCTIONAL DESCRIPTION

11-5835-243-34/EE641-AA-MMI-010/E154

MTT/TO

31S3-4-110-1

b. Reverse Tape Motion. In the tape reverse mode

terclockwise (fig. 2-2). Tape tension is developed in

both belt idlers and the floating pressure roller are

a similar manner to that described for forward tape

driven clockwise and the reels are driven coun-

motion.

Section Il. DETAILED FUNCTIONAL DESCRIPTION

2-6. Logic Definitions

c . Output Driver Capabilities.

(1) Standard Voltage Levels:

a. Input/Output (I/O) Logic Level Definition The

LOW level (logic 1): . . . . . . . . . .0.2 to +0.5 volt

following logic definitions are used to describe the

HIGH level (logic 0): . . . . . . . . . +2.5 to +4.5 volts (5.5V max.)

I/O logic requirements:

(2) Standard Current Levels:

(1) LOW. Indicates the relatively low input

Low (logic 1)". . . . . . . . . . . . . . . . 100 mA maximum

level or pulse to the line receiver that controls the

HIGH (logic 0):. . . . . . . . . . . . . . Outputs are open collector

and require an external pull-

active state of that functional (logic '1').

up resistor 220 to 330 ohms

(2) HIGH. The relatively high input level or

nominal.

pulse that indicates logic `0'.

2-7. Digital Read Write Circuit Description

(3) PULSE. A relatively low level which has a

time duration of less than 10 microseconds.

a. General. The tape transport uses three digital

(4) LEVEL. A relatively low level which has a

read/write circuit cards (A1, A2, A3). Each card

time duration of greater than 10 microseconds.

contains three identical digital read/write amplifier

b. Input Requirements. Input requirements for

sections, providing a total of nine read/write data

the tape transport are listed below:

channels. For example, AR1 serves as read amplifier

(1) Standard Voltage Levels:

for channels 3, 6, or 9 depending on card location

LOW level (logic l): . . . . . . . . . .0 to +l.2 volts

(XA1, XA2, or XA3). This paragraph describes just

HIGH level (logic 0): . . . . . . . . . +2.5 to +4.5 volts

one of the read/write amplifier sections on a circuit

( 2 ) Standard Current Levels:

card, but applies equally to all nine. Use the Digital

LOW (logic l): . . . . . . . . . . . . . . . + 0.1 mA maximum (from

Read/Write Circuit Card Functional Block Diagram

receiver)

(fig. 2-3) and the schematic diagram (fig. FO-2),

HIGH (logic 0): . . . . . . . . . . . . . . - 0 . 1 m A m a x i m u m ( f r o m

with the following description.

receiver)

2-5