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region close tu the screen. Equipment to test
tube performance is described, including ultraviolet
mapping and electronic detection of the
axis. Source 6/6 -220.
How to Specify UHF Amplifieres, by the Ens g
Staff, Applied Research Inc. "El. Eq." May
1956. 3 pp. An outline, from the manufacturer's
point of view, of engineering considerations
which will lead to proper specification of
UHF amplifiers. Source 6/6 -221
On the Lighting of Television Scenes and the
Lighting Equipment of the Baden -Baden Studio.
by G. Rosenbaum. "Tech. Haus." 1/2, 1956.
3 pp. The requirements and possibilities of
lighting systems in TV are outlined and the
particular solution selected for the Baden -
Baden station is described. Source 6/6 -222
The Background -Projection Equipment in the
Baden -Baden Studio, by O. Schulze. "Tech.
Haus." 1/2, 1956. 4 pp. This equipment permits
a still picture to be projected into the
television scene to serve as a background, thus
reducing the otherwise necessary scenery. A
transparency is used for this purpose. Extensive
cooling, i.e., a heat absorption filter as
well as a cooling trough are provided. Source
6/6 -223
Electronic Switches for Television, by A.
Spooner. "El. Eng." May 1956. 4 pp. A number
of types of electronic changeover switches
are considered, with particular reference to
the cause of switching transients. A new stable
diode -type switch is described which gives a
transient free changeover lasting a fraction of
a minusecond. This switch has been used for
replacing an arbitrarily shaped area of one TV
picture with the corresponding area from another
picture to effect scenery economy. Source
6/6 -224
111:2==)-
TRANSMISSION LINES
Non -Uniform Transmission Lines as Impedance
Transformers, by J. Willis and N. Sinha. "Proc.
BIEE" Mar. 1956. 7 pp. The equation for the
reflection coefficient at one end of a non-uniform
transmission line, matched at the other
end, is considered, and an approximate form
of solution is suggested which enables such
lines to be designed for optimum performance
as matching sections. A number of examples
are calculated and the results compared with
lines previously described in the literature.
Source 6/6 -227
Basic Considerations Concerning the Synthesis
of Lossless Four -Terminal Networks from Continuous
None -Uniform Lines, by H. Meinke.
"Nach. Z." Mar. 1956. 8 pp. The equations for
non -uniform transmission lincs with a continuously
varying parameter, i.e., either the dimensions,
the dielectric constant or the permeability,
are grouped as to the type of mathematical
functions involved. A polynominal
representation of the characteristic impedance
permits the synthesis of lossless 4- terminal networks
from non -uniform transmission lines.
Examples involving wide -band transformation
and matching are included. Source 6/6 -228
On the Behavior of Electromagnetic Waves in
Circular Wave Guides in the Region of the
Cut -off Frequency and Considering a Finite
Wall Conductivity, by W. Schaffeld and H.
Bayer. "Arc. El. Uber." Mar. 1956. 9 pp. Formulas
for the propagation constant, the attenuation
constant, the phase constant, and the
wavelength for all TE and TM modes are derived
for comparatively small skin depth. The
problem of stabilizing a reflex Klystron coupled
to a resonant line is treated. Source 6/6 -229
Investigations on the Energy Exchange and
the Field Distribution of Parallel Surface -Wave
Transmission Lines, by D. Marcuse. "Arc. El.
Uber." Mar. 1956. 8 pp. The interacting wire
wave guides are considered as a two-wire system.
If the two guides are identical, the total
current will be coupled over to the other guide
after a certain distance. The arrangement of
a different type guide will disturb the initial
field concentration. Source 6/6 -230
An Approximate Method for the Investigation
of the Distortions of Measuring Pulses when
Transmitted by Coaxial Cables, by H. Larsen
and H. Martin. "Freq." Mar. 1956. 12 pp.
Mathematical analysis leads to a graphical
method to establish the pulse resulting from
the transmission of an arbitrarily shaped pulse
through a coaxial cable with known transfer
characteristic and its deviations from the average
value. The graphical method relies on
sampling of the initial pulse at repeated intervals.
Numerical examples are included. Source
6/6 -231
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TUBES
The Motion of Electrons in the Interelectrode
Space of a Diode During Rapid Variation of
the Plate Voltage, by N. Ivanov. "Radiotek."
Jan. 1956. 7 pp. The paper develops the bases
for the numerical integration of the motion of
the electrons, taking the effect of space charge
into account. Thorough mathematical analysis
is given ; graphs for the motion of the electrons
in the space charge of the diode are constructed
and analyzed. Source 6/6 -232
The Current Division in Electron Tubes in the
Presence of Several Positive Electrodes and
for Low Current Densities, by H. Goellitz.
"Hochfreq." Jan. 1956. 8 pp. The computations
of the expected current division in a pentode
is based on limiting electron paths which separate
the paths of electrons traversing the suppressor
grid from the paths of the return electrons.
Space charge effects are neglected.
Source 6/6 -233
The Design of High -Power Traveling -Wave
Tubes, by M. Chodorow and E. Halos. "Prue.
IRE" May 1956. 10 pp. Discussion of the problems
involved in designing traveling -wave tubes
in the range of pulsed powers of the order of
a megawatt. Suitable circuits are described,
together with their advantages and limitations.
Source 6/6 -234
The Multi -Reflex Klystron as a Transmitting
Valve in Beam Transmitters, by F. Coeterier.
"Phil. Tech." May 1956. 6 pp. The first part
of this article develops the theory of the tube
and shows that the optimum transit time of
the electrons as a function of the moment of
time at which they pass through the resonator
enables the requisite potential curve to be
easily established between the repeller electrodes.
It is then demonstrated that the large
bandwidth of the tube is due to its low elecronic
admittance. Source 6/6 -235
A Grounded Grid Valve System with High Stability
Characteristics, by F. Exley and R.
Young. "El. Eng." May 1956. 2 pp. High stability
with grounded grid tubes in coaxial line
cavities is obtained by converting lighthouse
tubes into double ended ones ; i.e., a physical
arrangement is produced in which the anode
and grid cavities are disposed on opposite
sides of the common grid plane. An oscillator
is considered in detail. Source 6/6 -236
A New Steep -Characteristic Multi -Grid Tube
and Its Application in Pulse and Switching-
Circuit Engineering, by K. Gosslau and W.
Guber. "Freq." Mar. 1956. 7 pp. Structural
details of a fine -wire type beptode (V 108)
with 3 successive fine -wire type grids is described.
Two of these grids are control grids
having a mutual conductance of 13mA /V and
7.5mA /V, respectively. There are two independent
plates; a high plate current is obtained.
Tube data are presented and applications discussed.
Source 6/6 -237.
Tube -Characteristic Changes and Equipment
Reliability, by the Application Engineers of the
Advisory Group on Electron Tubes. "Tele-
Tech" June 1956. 3 pp. Interpretation of the
results of life tests to indicate the probability
of failure under dynamic conditions. Two forms
are employed -the "ogive" or cumulative frequency
distribution curve, and the "bell-
shaped" frequency distribution curve. Source
6/6-253
Air Cooling a Finned Magnetron, by M. Mark.
"Tele-Tech" June 1956. 3 pp. Increased power
demands on magnetrons, and their use in airborne
equipment has created a need for a light
weight, economical cooling system. Forced air
cooling, using properly designed cooling fins, is
described as a logical solution. Source 6/6 -254
Peaking and Interphase Transformers for
Thyratron Control, by P. Chin and E. Moyer.
"El. Mfg." May 1956. 9 pp. Discussion of the
use of the peaking transformer for positive
triggering of thyratrons in straight ac and ac
plus dc control circuits. Benefits of interphase
transformer windings in multiple rectifier circuits
are cited. Source 6/6 -255
Alkof#
U. S. GOVERNMENT
Research reports designated (LC) after the
price are available from the Library of Congress.
They are photostat (pho) or microfilm
(mie), as indicated by the notation preceding
the price. Prepayment is required. Use complete
title and PB number of each report
ordered. Make check or money order payable
to "Chief, Photoduplication Service, Library of
Congress," and address to Library of Congress,
Photoduplication Service, Publications Board
Service, Washington 25 D. C.
Orders for reports designated TOTS) should
be addressed to Office of Technical Services,
U. S. Department of Commerce, Washington
25, D. C. Make check or money order payable
to "OTS, Department of Commerce." OTS reports
may also be ordered through Department
of Commerce field offices.
When an agency other than LC or OTS is
the source, use the full address included in the
abstract of the report. Make check or money
order payable to that agency.
Thermal Evaluation of Air -Cooled Electronic
Equipment (PB 119267), by W. Robinson and
J. Barton, Ohio State U. Aug. 1953. 139 pp.
Mic $6.90, pho $21.80. (LC) Methods are presented
for the calculation of forced- convective
and radiant heat transfer of external and internal
aircraft skin surfaces and of equipment
case surfaces of different configurations.
Evaluation procedures are given for electronic
systems installations operating under steady -
state thermal conditions. Source 6/6 -1
Thermionic Emission from Semiconductors
(PB 119240), by E. Kane, Cornell U. Dec.
1954. 108 pp. Mic $5.70, pho $16.80. (LC)
Subjects include: the basic emission equation;
the effects that the screening of fields in semiconductors
may have on the thermionic emission;
the Schottsky effect in semiconductors;
and the ways in which current flow may alter
138 Tele -Tech & ELECTRONIC INDUSTRIES June 1956