M450A — Program Amplifer

M450A PROGRAM AMPLIFIER

The H450A Program Ampl ifier is a hig h performance a ud i o am- plif ier desig ned for pr-c te s st on a t appl ications. I t i s used particula rly in applications wh i c h requir e out put leve ls up to +36 dBm into eithe r a 150 or 600 ohm l oa d. The M450A must al ways be used in conju nction with the WBS output tr <lns f o r me r t y pe 70-7. The tra nsformer i s no t part of t he amp1 i fi e r assembl y en d mus t be or dered and mounte d s e pe- r e t.e l y .

The +36 dBm output capabflity of the M4S0A provides the ob vi o us ad vantage o f inc reas ed ou tp ut he a d r oom i n prog r <lm a mpl i f i er applicatio ns . Accordi ngly, t he amplifier is recommende d t o satisfy systems r e q uir e me nt s when higher th an +B dBm nomi nal output le vels are speci fied or wheneve r add itional he <ldr oo m is a p re requisite .

Addi tiona ll y, th e amplifi e r, with t he t ranSformer str appe d f o r 150 ohm may also be u t il i z e d t o pr o v i de up t o e ig ht ( 8 ) output s plits a t 600 o hm e a ch <I t a max imum out p u t l e vel o f +24 dBm. I n all aspects, othe r t ha n ou tput l o ad and power capa b il ity, t he M4 50A i s id e n t ic a l in its c be r-ec t e r t s t t c s to t he M450 .

a .c ps BS W :// tp ht

2- 1

WARD -BECK SYST E MS LTD .

CI RCUIT DESCRI PTI ON H4s 0A PROG RAM AHPLI FIER

The two ha lves of the i npu t signa l are a ppli e d to p in s 4 i1nd 6 o f the e dge con nec to r a nd then proc ee d via on -board r e si s t or s t o pin s 6 and 8 of 11 presenti ng a ba lan c e d i nput o f "ppro.i - lIate ly sk o h.. to the s ig nal sou rce . The tw o se ctio ns of II are followed by powe r booste r t un s is- to rs Ql , Q2, Q3 and 04 .

Pi ns 6 .lin d 8 of 11 a re vi rtually at ground potential fr OIl a signal standpoi nt and H is illpractical t o e e e s ure a signal voltage at these poi nts . The output of II , pin 1 is sUlllled t hrou gh R13 to pi n 80fll. Thus, at CIS , t he SU II o f the t wo halves of the input sig na l wi ll be present.

The gain of the H4s0A lIay be varied fr OIl 32 t o 48 dB by exte r- na l resistance cOllblnations as s ec ta tee wH h pins 9 , 10 a nd 11. Effec tive ly t h is changes t he feed bac k loop between pins 13 and 8 of 11. Since the selection of th e ga in of each allplifie r is de t e r ll i ne d by connecti ons lIade on t he r ec ept e c l e r e t he r t han t ns tee the ,"p lif ie r, a ll H4 50A eep l t t t e r s with in any given sys tell ca n be f ree ly i n terc ha nged withou t afff!ct i ng systell specifications and ope ra tion . Foll owi ng t he p r e e e p f t r te r o utput a t CI S is a 12 d8 per octav e low pus fl1te r ccap r-t s ed of R22 , Rs2 , R23, R24 , C16 , C17 , C18 a nd C19 , li mit in g th e ba ndwi dth bey o nd the au d i o pa.ss blind . The s ig na l is t hen f ed t o pi n 6 o f 12 and s ubs eque n t j y t o t r e n- sis to rs Q9, Ql0 , Q11 a nd Q12 . Thes e tr a ns i sto r s cOllpriseone half of t he powe r se l ec t io n of the a c t ivel y bat a nced allpl ifier o u t p ut. The slg n. l fr o", th i s half is fe d t hro ugh C23 t o p in 13 o f the e d ge co nne c to r. The si gnal f o r the s e cond half o f t he a llpl t rte r o u tp ut is ro u ted to p i n 8 of 12 and f o ll owe d by t r e n- sistor s Qs , Q6, Q7 a nd Q8. C28 ser ves to c ou pl e t he sig na l t o pin 12 o f th e e dg e con ne c to r . a .c ps

In all tn s t ences where the H4s 0A is us ed , its outp u t t e rmi na ls 12 a nd 13 must be wire d t o the i nput term ina ls 1 and 2 of a BS

was type 70 -7 t r an s fo rrae r . The seconda ry of t h is t r e ns rc r-ne r c a n be s t ra ppe d to f e ed e it he r ill 150 o r a 600 ohm lo ad. W :// tp ht

3-1

WARe - BEC K S YST E MS LT O .

CIRCUIT DESCRI PTION H450A PROGRAM AMPLI FI ER

The b i· po hr supp l y 'to l u ge o f t25 vel t s dc 15 f ed 'tta t sc t a- t t cn d i od e s CRI an d CR2 t o CJ lind C4 . t 24 vc t ts i s use d to s upp ly th e o utpu t lind dr i't er s ta ge s • • ith all ot he r c i r cu i ts b e i n g s up pl ie d . !th t 16 vej r s . As I result of th e sy • • e t ry o f t he e n ti r e c ircuit. th e de 'to lta ge s a t p ins 1 lin d 13 of ZI .ill be nOllinlllll)' +0.6 volts. The vo lt iges I S . e as u red I t th e junc- ti o ns o f Rll /R12. R20/R2 1 , R2 7/ RJ O. RJ9 / R4 2, c o l lec to rs of Q6/Q8 lind Q10/Q 1Z .111 be It 0 vol ts tlO IlIV . The s upp l y current will be l ess than 50 mA (typi c ally 40 .A ) in the quiescent state, and 10111 1 rise to 250 lilA at full output of +36 dBm delivered to a l oa d of either 150 or 600 Ohms, as deter- min ed by the strapping of the 70-7 output transfor mer.

a

"450A PROGRAHAHPLIFIER

PART DESCRIPTIOH HFG PART HUMBE R

C1 Capa~ itor 22 ~F/25 Y '" Sf!lIens B41313·~5226-Z C2 C3

" C5 33 0 uf / 6 Y Kellet T390F 337K 006AS C6 C7 10 0 pF Ph ilips 2222-638-70101 C8 0 .047 uF As e lco CQ92-HC -473H CO 68 0 0 pF CQ92-HC-682 H e10 10 0 pF Phil ip s 2222-638-70 10 1 ell 220 pF 22 22-630 - 0 322 1 C12 330 0 pF A s~lco CQ92-MC-332 M C13 0 .0 4 7 CQ92- MC-47 3M e14 220 p F Phili ps 2222-630-0 322 1 Cl5 33 u FIlO Y xemet T39 0D336K0 10AS

elG 1 50 0 pF Asel co CQ92-HC- 152H C17 470 pF Ph ~ 1 f ps 2222-630-03471 C18 150 pF 2222-638 -70 151 C19 47 pF 2222-638-70479 e20 10 0 pF 2222-638-70101

ell 0.027 Aselco C092-MC -2 73M m C23 1 0 0 0 pF 330 uF /6Y " Ke_et C092-M C- 102M T390F 33 7K006 AS C24 0.027uF As e lco C092 -MC-2 73H C25 100 pF Phil ips 2 222 -638 - 70101

CZG 100 pF 2222-638-70101 m 1000 p F Aselco CQ92-MC- 102M e28 330 uF/6 Y xeee t. T390F337K006AS C29 Fa c t o r y Selected (30 2 . 7 pF Philips 2222-638-03278 a .c

e31 ps

C32 BS

C33 e31 10 0 pF 2222-638-70 10 1 W

e35 220 pF 2222· 630 - 03 22 1 ://

(JG tp

<37 10 p F 22 22-6 38-1010 ht

5-1

WA R D -B E CK SYSTEMS LTD .

PARTS LI ST

M450A PROGRAM AMPLI FIER

PART