CW AVERAGE Position of Function Switch

plier circuit. The metering signal is

respective load resistors, R712,

coupled to the negative terminal of M701

R713, R714 and R715.

a n d continues through the meter move-

(2) Plate circuits. The plates of each

ment to the positive terminal of M701.

s e c t i o n of cathode follower V702

b. S702 Front, Section Y. C o n t a c t i s

are directly connected to the +150-

m a d e between terminals 1 and 2 so that

volt output of the power supply.

the metering signal has a path of continuity

(3) Detailed circuit description. S i n c e

through IF. CATHODE FOLLOWER ADJ

a detailed circuit description of the

s w i t c h S704, which normally is closed.

c a t h o d e follower depends on the

Switch S704 is provided as a chassis ad-

p o s i t i o n of function switch S702,

justment control for peaking the if. cathode

t h e description of current flow in

f o l l o w e r stages in the if. amplifiers of

t h e metering circuit is covered in

turning units 2, 3, and 4. (There is no if.

t h e following paragraphs of func-

c a t h o d e follower in tuning unit 1.) Find

tion switch operation.

resistor R717 is inserted in the meter

path as an additional meter multiplier

18. CW AVERAGE Position of

w i t h the switch in its open position. An

Function Switch

a d d i t i o n a l meter multiplier is necessary

(fig. 8)

because adjustment of the peaking coils in

T h e following subparagraphs describe

the if. cathode followers of tuning units 2,

the circuit conditions for the C W AVER-

3 , and 4 requires overdriving the meter

AGE position of function switch S702. Fig-

b e y o n d its full-scale indication. Capacitor

u r e 8 shows that the output of cathode

C 7 0 8 damps the meter movement when

f o l l o w e r V702A is developed across load

M E T E R DAMP switch S703 is thrown to

r e s i s t o r R712 and cathode-bias resistor

its ON position or held in its MOM posi-

R 7 1 3 . With SIGNAL ATTENUATOR DB

t i o n . This switch, which provides an ac

wafer switch S701 in any position except

p a t h through capacitor C708 and resistor

0 CW ONLY, the signal is coupled through

R 7 2 3 across the meter terminals, is used

meter multiplier resistor R722 to ter-

when low-signal levels cause erratic meter

minal 2 of function switch S702 (rear). In

p o i n t e r fluctuations. The metering signal

the 0 CW ONLY position of S701, resistor

h a s a return path fo the +150-volt power

R 7 2 2 is bypassed by the wiper and ter-

s u p p l y through the normally closed con-

m i n a l 2 of the switch; the meter is then

tacts of switch S704, fixed resistor R716,

1 0 - d b more sensitive than in any other

ZERO ADJ control R715, and V702B.

p o s i t i o n of S701 (para 12c). The various

c. S702 Front Section Z. C o n t a c t i s

s e c t i o n s of fiction switch S702 provide

made between terminals 2 and 3 only in the

a path of continuity for the metering signal

C W AVERAGE position of the function

as follows:

s w i t c h . Under this condition, the 6.3-volt

a c output from the power supply passes

a. S702 Rear, Section X. Contact is

through feedthrough capacitor C751 and rf

m a d e between terminals 2 and 3 so that

coil L711 in the filter box, to terminal 18

the metering signal has a path of continuity

o f main unit receptacle J701. The mating

through rf filter FL702. This filter houses

plug at the rear of the tuning unit applies

feedthrough capacitors C706 and C707, rf

this 6.3-volt ac potential to the heaters of

c o i l s L720 and L721, and fixed resistor

t w o thermal relays in the detector and

R725. Resistor R725 functions as a meter

e l e c t r o m e t e r assembly. The load imped-

multiplier with no phone plug inserted into

a n c e of the two detectors in the electro-

R E C O R D E R EXT METER jack J704. The

meter assembly is reduced with the heaters

i n s e r t i o n of a phone plug into jack J704

o f the relays energized. This action is

r e m o v e s R725 from the metering signal

e q u i v a l e n t to lowering the time-constant

path and substitutes the internal resistance

o f either the remote meter or a record-

i n the detector charging circuit. The pur-

i n g meter (depending on the device used

pose of this circuit is to enable the elec-

a t the remote site) into the meter multi-

trometers to measure the average envelope