![Page 1: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/1.jpg)
Curs 102014/2015
![Page 2: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/2.jpg)
Stabilitatea amplificatoarelor de microunde
![Page 3: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/3.jpg)
Obtinem conditiile ce trebuie indeplinite de ΓL pentru a obtine stabilitatea
1in1
1 22
211211
L
L
S
SSS
1out 11 11
211222
S
S
S
SSS
Obtinem conditiile ce trebuie indeplinite de ΓS pentru a obtine stabilitatea
![Page 4: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/4.jpg)
![Page 5: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/5.jpg)
Proiectare pentru castig maxim
![Page 6: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/6.jpg)
Castig maxim de putere se obtine cand
Pentru retele de adaptare fara pierderi
Pentru tranzistor bilateral (S12 ≠ 0) Γin si Γout se influenteaza reciproc deci adaptarea trebuie safie simultana
*Sin *
Lout
2
22
2
222
21max
11
11
LinS
LST
S
SG
2
22
22
212max1
1
1
1
L
L
S
TS
SG
![Page 7: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/7.jpg)
Adaptarea simultana se poate realiza numaipentru amplificatoarele neconditionatstabile la frecventa de lucru, si solutia cu |Γ|<1 se obtine cu semnul –
1
2
1211
2
4
C
CBBS
2
2
2222
2
4
C
CBBL
*22111
22
22
2
111 1
SSC
SSB
*11222
22
11
2
222 1
SSC
SSB
![Page 8: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/8.jpg)
Se alege una din cele doua solutii posibile Similar pentru adaptarea la iesire
8.163
9.133
1.150
1.1502
477.3
477.3Im Sy
74
10618074sp
7.176686.0L 1Re Ly L 2cos
3.133
3.13327.176
25180155
3.1581807.21
885.1
1
2Im
2
L
LLy
1.62
9.1171801.62sp
0.25
3.158
3.133
3.1332
885.1
885.1Im Sy
1.62
9.117sp
![Page 9: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/9.jpg)
![Page 10: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/10.jpg)
![Page 11: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/11.jpg)
Proiectare pentru castig impus
![Page 12: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/12.jpg)
Deseori este necesara o alta abordare decat"forta bruta" si se prefera obtinerea unuicastig mai mic decat cel maxim posibilpentru: conditii de zgomot avantajoase (L3 + C9)
conditii de stabilitate mai bune
obtinerea unui VSWR mai mic
controlul performantelor la mai multe frecvente
banda de functionare a amplificatorului
![Page 13: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/13.jpg)
Se realizeaza cu asumarea unilaterala a amplificatorului
Castig maxim
2
22
2
212
11
max1
1
1
1
SS
SGTU
2
22
2
2
11
22
211
1
1
1
L
L
S
STU
SSSG
012 S
Permite tratarea separataa intrarii si iesirii
11Sin
*11SS
*22SL
![Page 14: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/14.jpg)
Permite estimarea erorii induse de ipotezatranzistorului unilateral
Se calculeaza U si abaterea maxima si minima a lui GTU fata de GT
aceasta abatere trebuie prevazuta in proiectare ca rezerva pentru castigul maxim
221
1
1
1
UG
G
U TU
T
2
22
2
11
22112112
11 SS
SSSSU
UdBGdBGU TUT 1log201log20
![Page 15: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/15.jpg)
Daca ipoteza tranzistorului unilateral estejustificata:
2
22
2
2
11
22
211
1
1
1
L
L
S
STU
SSSG
2
11
2
1
1
S
SS
SG
2
22
2
1
1
L
LL
SG
2
210 SG
![Page 16: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/16.jpg)
Castig maxim pentru adaptare complex conjugata (putere) la intrare
Pentru oricare alta retea de adaptare
2
11
2
1
1
S
SS
SG
2
11
max1
1
SGS
*
11SS
2
11
max2
11
2
1
1
1
1
SG
SG S
S
SS
![Page 17: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/17.jpg)
5.1SG
0.1SG
5.0SG
Cercuri
![Page 18: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/18.jpg)
2
11
2
1
1log10
S
SS
SdBG
*11
max SSSS
GG
![Page 19: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/19.jpg)
Ecuatia unui cerc in planul complex in care reprezint ΓS Interpretare: Orice punct ΓS care reprezentat in planul
complex se gaseste pe cercul desenat pentru gcerc = Gcerc/GSmax va conduce la obtinerea castigului GS = Gcerc
Orice punct in exteriorul acestui cerc va genera un castig GS < Gcerc
Orice punct in interiorul acestui cerc va genera un castig GS > Gcerc
2
11
2
11
2
11
*11
11
11
11 Sg
Sg
Sg
Sg
S
S
S
SS
SSS RC
2
11
*11
11 Sg
SgC
S
SS
2
11
2
11
11
11
Sg
SgR
S
SS
![Page 20: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/20.jpg)
Cercurile se reprezinta pentru valorile cerute in dB Este utila calcularea GSmax si GLmax anterior
![Page 21: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/21.jpg)
Proiectare pentru zgomot redus
![Page 22: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/22.jpg)
Factorul de zgomot F caracterizeaza degradarearaportului semnal/zgomot intre intrarea si iesireaunei componente, cand la intrare se aplica o putere de zgomot de referinta (T0 = 290K)
KToo
ii
NS
NSF
2900
![Page 23: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/23.jpg)
Factorul de zgomot F nu caracterizeaza direct degradarea raportului semnal/zgomot intre intrarea siiesirea unei componente, cand la intrare se aplica o putere de zgomot diferita de cea de referinta
KToo
ii
NS
NSF
2900
![Page 24: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/24.jpg)
In general, puterea de zgomot la iesire se obtinecu doua componente: o putere datorata zgomotului de intrare amplificat cu
castigul G (depinde de puterea de zgomot de la intrare)
o putere de zgomot generata intern de dispozitiv(care nu depinde de puterea de zgomot de la intrare)
![Page 25: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/25.jpg)
Estimarea puterii de zgomot adaugate se poate face plecand de la definitia factoruluide zgomot:
010 ,29022
11
NNKTNS
NSF
111 NSP 222 NSP
GNFS
SNFN 0
1
202
GNFGNN 002 1
![Page 26: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/26.jpg)
Se identifica cei doi termeni: zgomotul de intrare amplificat
zgomotul adaugat intern Pentru o situatie in care la
intrare nu am zgomotul de referinta (N1 ≠ N0)
111 NSP 222 NSP
GNFGNN 002 1
GNFGNN 012 1
![Page 27: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/27.jpg)
21 GGGcas
222 NSP 111 NSP 333 NSP
111 NSP 333 NSP
101112 1 GNFGNN
202223 1 GNFGNN cascascas GNFGNN 013 1
2022101113 11 GNFGGNFGNN
20221012113 11 GNFGGNFGGNN
![Page 28: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/28.jpg)
21 GGGcas
222 NSP 111 NSP 333 NSP
111 NSP 333 NSP
cascascas GNFGNN 013 1
20221012113 11 GNFGGNFGGNN
11
2
1
1 FG
FFcas
2102022101 111 GGNFGNFGGNF cas
![Page 29: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/29.jpg)
Ecuatia Friis (!coordonate liniare)
11
2
1
1 FG
FFcas21 GGGcas
321
4
21
3
1
21
111
GGG
F
GG
F
G
FFFcas
![Page 30: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/30.jpg)
Formula lui Friis arata ca
zgomotul unor circuite in cascada este in mare parte determinat de circuitul de la intrare
zgomotul introdus de celelalte circuite este redus
▪ -1
▪ impartire la G (de obicei supraunitar)
321
4
21
3
1
21
111
GGG
F
GG
F
G
FFFcas
![Page 31: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/31.jpg)
Formula lui Friis, efecte: in amplificatoare multietaj: e esential ca primul etaj de amplificare sa fie nezgomotos,
chiar cu sacrificarea in parte a castigului urmatoarele etaje pot fi optimizate pentru castig
pentru un singur amplificator: la intrare e important sa introducem elemente
nezgomotoase (reactive, linii fara pierderi) circuitul de adaptare la iesire are o influenta mai mica
(zgomotul este generat intr-un punct in care semnalul estedeja amplificat de tranzistor)
321
4
21
3
1
21
111
GGG
F
GG
F
G
FFFcas
kTBRV efn 4)( kTBPn
![Page 32: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/32.jpg)
ATF-34143 at Vds=3V Id=20mA. @5GHz S11 = 0.64139°
S12 = 0.119-21°
S21 = 3.165 16°
S22 = 0.22 146°
Fmin = 0.54 (tipic [dB] !)
Γopt = 0.45 174°
rn = 0.03
![Page 33: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/33.jpg)
![Page 34: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/34.jpg)
101SSR
![Page 35: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/35.jpg)
10010PSR
![Page 36: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/36.jpg)
101SLR
![Page 37: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/37.jpg)
10010PLR
![Page 38: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/38.jpg)
Caracterizat de 3 parametri (2reali + 1 complex):
Γopt reprezinta coeficientul optim de reflexie la intrare
optN
nZ
RrF ,,
0
min
2
min optS
S
N YYG
RFF
22
2
min
11
4
optS
optS
nrFF
S
SS
ZY
1
11
0 opt
opt
optZ
Y
1
11
0
minFFoptS
![Page 39: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/39.jpg)
![Page 40: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/40.jpg)
![Page 41: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/41.jpg)
Cercuri
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Γopt = 0.45 174°
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Se noteaza cu N (parametru de zgomot)
N constant pentru F constant
2min
2
2
141
opt
nS
optS
r
FFN
2** 1 SoptSoptS N
NN optoptoptSoptSSSS ***2*
11
2
*
**
*
N
N
N
opt
optopt
optSoptS
SS 2
2
1
N
opt
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Locul geometric al punctelor caracterizate de factor de zgomot constant este un cerc
Interpretare: Orice punct ΓS care reprezentat in planulcomplex se gaseste pe cercul desenat pentru Fcerc vaconduce la obtinerea factorului de zgomot F = Fcerc
Orice punct in exteriorul acestui cerc va genera un factor de zgomot F > Fcerc
Orice punct in interiorul acestui cerc va genera un factor de zgomot F < Fcerc
1
1
1
2
N
NN
N
optopt
SFFS RC
1
NC
opt
F1
12
N
NN
Ropt
F
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Se observa ca zgomotul generat de tranzistordepinde numai de modul in care se realizeazaadaptarea la intrare
Se poate obtine un minim (Fmin care esteparametru de catalog pentru tranzistor)
Daca se urmareste realizarea unui amplificatorde zgomot redus (LNA) o metoda uzuala este: adaptarea la intrare a tranzistorului din considerente
de zgomot adaptarea la iesire utilizata pentru compensarea
castigului (daca sunt elemente cu pierderi adaptareala iesire poate adauga zgomot propriu, dar nu se influenteaza in nici un fel zgomotul generat de tranzistor)
![Page 47: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/47.jpg)
De obicei un tranzistor potrivit pentru implementarea unuiLNA la o anumita frecventa va avea cercurile de castig la intrare si cercurile de zgomot in aceeasi zona pentru ΓS
![Page 48: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/48.jpg)
ATF-34143 at Vds=3V Id=20mA. @5GHz S11 = 0.64139°
S12 = 0.119-21°
S21 = 3.165 16°
S22 = 0.22 146°
Fmin = 0.54 (tipic [dB] !)
Γopt = 0.45 174°
rn = 0.03
![Page 49: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/49.jpg)
Amplificator de zgomot redus La intrare e necesar un compromis intre
zgomot (cerc de zgomot constant la intrare)
castig (cerc de castig constant la intrare)
stabilitate (cerc de stabilitate la intrare)
La iesire zgomotul nu intervine (nu existainfluenta). Compromis intre:
castig (cerc de castig constant la iesire)
stabilitate (cerc de stabilitate la iesire)
![Page 50: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/50.jpg)
In cazul particular prezent GLmax = 0.21 dB, amplificatorular putea functiona cu iesirea conectata direct la o sarcin de 50Ω
Absenta retelei de adaptare la iesire nu conduce la o pierdere importanta de castig, dar elimina posibilitatea ca prin reglaj sa se compenseze compromisul castig/zgomotintrodus la intrare
094.0
112
22
2
11
22112112
SS
SSSSU dBdBGdBGdB TUT 861.0783.0
83.171
1
1
12
22
2
212
11
max
S
SS
GTU dBdBGTU 511.12max
dBS
GS 289.2694.11
12
11
max
dBS
GL 215.0051.11
12
22
max
dBSG 007.10017.102
210
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Pentru reteaua de adaptare la intrare CZ: 0.75dB CCCIN: 1dB, 1.5dB, 2 dB
Aleg (Q mic banda larga) pozitia m1
![Page 52: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/52.jpg)
Daca se sacrifica 1.2dB castig la intrare pentru conditiiconvenabile F,Q (Gs = 1 dB)
Se prefera obtinerea unui zgomot mai mic
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Pozitia m1 de pe grafic
178412.0S 178;412.0 S
412.02cos 33.1142
8.31
2.146
33.114
33.1142
904.0
904.0Im Sy
1.42
9.137sp
S 2cos 2
1
2Im
S
SSy
![Page 54: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/54.jpg)
CCCOUT: -0.4dB, -0.2dB, 0dB, +0.2dB Lipsa conditiilor privitoare la zgomot ofera posibilitatea
obtinerii unui castig mai mare (spre maxim)
![Page 55: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/55.jpg)
Pozitia m2 de pe grafic
9.132;186.0 L
186.02cos 72.1002
1.16
8.116
72.100
72.1002
379.0
379.0Im Ly
7.20
3.159sp
9.132186.0L
L 2cos 379.0
1
2Im
2
L
LLy
![Page 56: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/56.jpg)
Se estimeaza obtinerea unui castig (in ipoteza unilaterala, ±0.9 dB)
Se estimeaza obtinerea unui factor de zgomot sub 0.75 dB (destul de apropiat de minim ~0.6 dB)
dBGdBGdBGdBG LST 0
dBdBdBdBdBGT 2.112.0101
![Page 57: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/57.jpg)
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Daca e necesar un castig mai mare decat celcare poate fi oferit de un singur tranzistor
Se utilizeaza formula lui Friis pentru a impartinecesarul de:
castig
zgomot
pe cele doua etaje individuale
![Page 60: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/60.jpg)
Adaptarea inter-etaje se poate proiecta in doua moduri:
adaptarea fiecarui etaj spre un Γ = 0 intermediar
![Page 61: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/61.jpg)
Adaptarea inter-etaje se poate proiecta in doua moduri:
adaptarea unui etaj spre Γ necesar pentru celalalt
![Page 62: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/62.jpg)
Amplificatoare de banda larga
![Page 63: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/63.jpg)
Se pot obtine prin un numar de tehnici de proiectare
1. Retele de adaptare care sa compensezescaderea castigului cu frecventa
2. Retele de adaptare rezistive
3. Reactie negativa
4. Amplificatoare echilibrate
5. Amplificatoare distribuite
6. Amplificatoare diferentiale
![Page 64: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/64.jpg)
2 Amplificatoare (identice) cu doua cuploarehibride 3 dB / 90° la intrare si iesire
BA GGj
S
2
21
BAS 2
111
BA FFF 2
1GjS
BA
21
011 BA
S
![Page 65: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/65.jpg)
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Conditia de sincronizare
intarzierea pe liniile de intrare (grila) egala cu ceade pe liniile de iesire (drena)
Castigul de putere
Castigul de putere fara pierderi
ddgg ll
2
22
4 ddgg
ddgg
ll
lNlNgdm
ee
eeZZgG
ggg j ddd j
4
22 NZZgG
gdm
![Page 67: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/67.jpg)
ddgg
ddgg
optll
llN
lnln
![Page 68: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/68.jpg)
Capacitatile de intrare in cele douatranzistoare in conexiune diferentiala aparconectate in serie
Se dubleaza astfel frecventa unitara
![Page 69: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/69.jpg)
Se utilizeaza structuri de circuit care sa faca conversiade la dispozitivele unipolare la cele diferentiale
cuploare hibride 3dB / 180°
"balun" (balanced - unbalanced)
![Page 70: Curs 10 2014/2015rf-opto.etti.tuiasi.ro/docs/files/DCMR_Curs_10_2014.pdf · 2014-12-17 · Se observa ca zgomotul generat de tranzistor depinde numai de modul in care se realizeaza](https://reader033.vdocuments.pub/reader033/viewer/2022041901/5e607584e3503c7e9f6e1399/html5/thumbnails/70.jpg)
Laboratorul de microunde si optoelectronica http://rf-opto.etti.tuiasi.ro [email protected]