Models 900CT & 900BT

Model 900 Series

Single Channel –

Certified

Front Panel Description

4

1784 Chessie Lane, Ottawa, IL 61350 • Tel: 800/252-7074, 815/434-7800 • FAX: 815/434-8176

e-mail: sales@freqdev.com

• Web Address: http://www.freqdev.com

Location of Front Panel Terminals and Controls

AB

C

D

E

F

G

H

I

J

K

L

M

A. POWER Status Lamp:

This red LED

indicates whether or not the power to the

analog filter circuitry of a Model 900CT/BT

Series instrument is ON.

With the power

switch in the ON position, the LED glows

continuously indicating internal DC power

levels are correct. If LED does not light when

power switch is in ON position, 1) reset

instrument by cycling POWER switch OFF

and ON, 2) Check line fuse.

For 900BT models only: If LED is flashing,

recharge batteries, approximately 30 minutes

of operation remains.

B. CORNER FREQUENCY

Selector Switch

(0-400Hz): This five position rotary switch

selects

the

100’s

digit

of

the

corner

frequency

designator.

The

switch

selectable values are 0, 100, 200, 300 and

400 in five discrete steps.

C. CORNER FREQUENCY

Selector Switch

(0-90):

This ten-position rotary switch

selects the 10’s digit of the desired corner

frequency between 0 and 90, in discrete

increments of 10.

D. CORNER FREQUENCY

Selector Switch

(0-9): This ten position rotary switch selects

the 1’s digit of the desired corner frequency

between 0 and 9 in discrete increments of 1.

E. MULTIPLIER

Selector Switch: This four-

position rotary switch multiplies by a factor of

either 0.1, 1.0, 10 or 100, the aggregate value

set on the 3 CORNER FREQUENCY selector

switches. (B, C & D)

F. GAIN

Switch:

This three-position toggle

switch selects an overall filter gain of 0, 10, or

20 dB.

G. BYPASS

Switch: OUT and IN setting of

this two position toggle switch routes the input

signal to the internal filter or around it,

respectively. E.g. OUT position - no Bypass,

the signal passes through the filter. In either

case, the gain switch remains operational.

H. INPUT

Switch: This three position toggle

configures the instrument for either differential

inputs (A-B), a single-ended input (A), or input

nulling ( ) which grounds both the (A) and (B)

input terminals.

I. & J. (A) and (B)

Input Terminals: This pair

of shielded, female BNC connectors accept

signal inputs (A) and (B).

The instrument

applies a non-inverting gain to input (A) and

an equal but opposite inverting gain to input

(B) while the GAIN switch sets the magnitude

of differential gain to 0, 10, or 20 dB.

The

BNC shields have been internally connected

to the instrument ground.

K. GROUND

( ) Terminal:

This “Banana”

type test jack provides neat and secure

access to the internal ground. This terminal

is

a

convenient

junction

for

grounding

external

system

and

measurement

instrumentation and/or apparatus.

L. OUT

Terminal: This terminal is a female

BNC connector.

The shield on the BNC is

internally connected to the instrument ground.

M. OFFSET

Adjust:

This adjustment is

intended to zero the offset that results from

the instrument’s own circuitry and does not

provide for wide range offset to remove dc

input signals.