1960
Mount ond Begg: Poramelrlc Devices ond Masers: An Annolaled Bibllogrophy
243
Correction
Leo Young, the autl1or of "Tables for Cascadcd Ho­
mogeneous Quarter-\1/ave Transformcrs," which ap­
pearcd on pages 233-237 in tlle Aprii, 1959 issue o{ thcsc
TRANSACTIONS, has requcsted that the following rcvi­
sions be made in his paper.
The values of Z1 and Z 2 for the four-scction (n = 4)
lransformers given in Tablcs IV to XIII are not quitc
optimum. In computing thcm, the positive roots of thc
fourth degree TchcbychefT polynomial were crroneous­
ly taken as ½{l ± 1/v'2) instcad o! [½(1 ± 1/v'2)] 11'. The
effect o{ this is to reduce the bandwidth by approxi­
mately the ratio of the incorrcct to thc com�ct outer
roots, that is, by a factor [½(1 1/ v'2) ]'" = 0.924. At
the same time, the match is improvcd near the center of
the band.
+
Twenty rcprcscntative four-section tmnsformers wcre
analyzed numerically. The bandwidth rcduction ap­
peared to be independent of R. and was about 1/15 bc­
low the greatest possible bandwidth for thc maximum
VSWR spccificù in Table HL For instant-e, thc stateci
60 per cent four-scction transformers (Table X) had
only 56 per cent bandwidth; and thc statcd 120 per cent
four-scction transformers (Table XIII) had only 112 per
ceut bandwidth, for the VSWR claimed in Tablc II I.
New tables for four-section transformcrs were com­
puted and are appendcd. These bave been checked out
by numerica[ analysis of repres(!ntative cases.
Various two- and thrce-section transformers given in
rny originai tables wcrc also checked by numerica! anal­
ysis, ;md found to give the predictcd frequency response.
FouR-SECTTOS QU41lTRR-WA\IF, Tu,.-s�OR&ll::IIS
lmpcdnncc
Ratio, R
1.00
1.2S
1.50
l.75
2.00
2.50
.l.00
4.00
5.00
6.00
8.00
IO .00
12.50
15.00
17 .50
20.00
25 .00
.30.00
40.00
50.00
60.00
80.00
100.00
Mnximally Fl.it
z,
1.00000
1.0140S
1.02570
I .03568
1.0H44
I .05933
1.07176
1.09190
1.10801
1.12153
1.14356
I. 16129
1.17961
I. 19500
I.208-l7
1.22035
I .24078
I.25SOJ
1.28632
1.30920
1.32853
1.36025
1.38591
z,
1.00000
1.07223
1.13512
1.19120
1.24206
I .332(}1
I .-11051
1.54417
1.65686
I.75529
1.92323
2.06509
2.21803
2 .J5186
2 .-47169
2.58072
2. 77447
2.9442.1
3.23�92
3.48136
J.69752
4 .06810
4.38263
13:indwidth =-0.10
Z,
1.00000
l.01-ll4
1.02S86
t .03591
1.04473
1.05972
1.07223
1.09250
1.10873
I .12235
l.l-H55
1.16242
1.18090
t.t9M8
1.21001
1.22200
1.24262
1.26()().1
1.28862
1.31174
1.33129
1.36338
1.38936
z,
1.00000
I.Oi232
1.13530
1.19146
1.24239
1.33252
1.41113
l. 54503
1.6579'1
I.75657
1.92490
2.06710
2.22044
2.35-10.5
2.47483
2.58419
2.77857
2.94891
3.24067
3.�
3.70517
4:.07741
4.39348
Bandwidth-0.20
Z,
1.00000
1.01440
t .02635
1.03659
l.0•1558
1.06088
1.073(�
1.09435
1.11093
1.12486
1.14758
1.16588
1.18483
1.20082
I. 21471
1.22703
1.24824
l. 26618
1.29564
1.31953
1.33974
1 .37297
1.39992
z,
1.00000
1.07260
1.13S84
1.1?224
1.24340
1.33396
1.41296
1.54760
1.66118
I.76043
1.92990
2.07315
2.22770
2.J<SJOJ
2.48426
2.59163
2.79089
2.96299
3.25798
.'J.50835
3.72816
4.10�44
4.42610
Bandwidth •0.30
z,
1.00000
1.01486
1.02719
1.03777
l.OH06
1.06287
1.07607
1.09752
1.11472
1.12917
1.15279
1.17184
1.19160
1.20829
I.22281
I .23571
t .25795
1.27679
1..10781
I .33302
1.35440
1.38965
1.41832
z.
l .00000
I .07.306
1.13673
1.19354
l.24508
1.33636
1.41603
1.55190
1.66660
l.76689
1.93828
2.08328
2.23985
2 .37700
2.50007
2 .6121J
2.81154
2.98659
3.28(i98
3.54228
3.76669
4 .15241
4.48078