Racal Instruments 9916 User Manual

Racal Instruments 9916

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4.37

During

states

0 to 8

of

IC23,

IC22</8

and

IC22b/6

are

at

'1

1

•

The

outputs

at

IC22</

10

and

IC22b/4

are

therefore

at

'0',

and

no

modification

is

made

to

the

b.c.d.

information

from

IC4.

During

state

9

IC27c!lO

goes

to

11'

if

the

'A'

Channel

is

selected

but

otherwise

remains

at

'0'.

IC22b/4

goes to 11'

if

either

LF

or

the

lA'

Channel

are

selected.

Thus, for

LF,

binary

010

(decimal

2)

is

added,

and

for

lA'

Channel

binary

111

(the

2's

complement

of

1)

is

added,

so

adding

two to

or

subtracting

1 from

the

b.c.d.

information.

Units

Indicators

4.38

The units in

which

the

display

should

be

read

are

indicated

by

LP2,

3

and

4.

These

are

I

it

according

to

the

encoding

of

the

logic

from

the

RESOLUTION

switch

and

the

CHANNEL

SELECT

switch

(LF

position)

in

IC15a,

b,

c

and

d.

Overflow

r.39

Overflow

of

the

10

7

store

is

indi

cated

by

a

'1

1

at

I

C4/

15

duri

ng

state

8

of

IC23.

If

overflow

occurs

IC14b/12

is

taken

to

'1

1

.

During

state

8

IC22q12

goes

to

'0',

and

at

the

negative

going

transition

of

the

10

kHz

signal

at

IC22q13,

IC14b/8

is

clocked

to

'0'.

This lights

LP6

to

indicate

that

overflow

has

occurred.

4.40

IC14b

is

returned

to

the

cleared

state

by a

'0'

at

pin

13

at

the

end

of

the

main

gate

period.

Gate

Indicator

4.41

The main

gate

waveform

is

inverted

by

IC7a.

When

the

main

gate

is

closed

I

C7q/2

is

at

'0'

and

031

turned

off.

Wi

th

the

main

gate

open

the

R

130/R

135

junction

can

rise

and

031

turns

on.

LP7

therefore

lights in

synchronism

with

the

main

gate.

~

",

I

I'

\.v . . , ,

~

.'

.

n('i-~

"""(~<..j

t

·,~

....

·-rVJ"'V'\_our.;:...~,\,

.t....-_

.........

..:.;

.....

:.;>~,

......

_

...

.l-

<-1-'

'"'"l...::f'V'""\

tA.-...c\

...

('.--,-\l,~

l\:....:.J-

lL...;

(_,'-...f""\_'"\.l

....

P('

Display

Bla~ki~';\

~,;

.

~'~"~·o"c~f.lL-C>

'-"'"''-''',

,~\,,~

,.,.".,<.1·'5

L-..\"-'E.

lG

':".I\0-"V-o

'.Ie

(C~'j~'J

.42

The

display

is

blanked

out

briefly

at

the

end

of

each

gate

period

while

the

readout

system

is

synchronising.

027

is

turned

off

by

the

trailing

edge

of

the

main

gate

pulse

(inverted

in

lC7a

and

differentiated

by

C78/R113).

The

resulting

short

negative

going

pulse

at

IC19</8

is

appl

ied

to

1

IC1/

4

and

blanks

the

display.

4.43

The

display

is

also

blanked

out

in

the

event

of

failure

of

the

10

kHz

synchronising

signal.

This

prevents

burn

out

of

the

numerical

~ndicator

which

is

enabled

when

failure

occurs.

One

digit

of

the

b.c.d.

output

of

IC23

is

applied

to

the

peak

to

peak

detector

C76,

D23, D24,

C77.

The

detector

output

turns on

026.

If

change

in

the

b.c.d.

digit

ceases

026

will

turn

off

and

IC19b

will

clamp

11CV

4

to

'0'.

4-6

9916Vol.2

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Racal Instruments 9916 Specifications

General

Brand	Racal Instruments
Model	9916
Category	Measuring Instruments
Language	English