TELE-TECH & - AmericanRadioHistory.Com

'ono/ ELECTRONIC SOURCES
Investigation of the Human Voice by Delayed
Speech Feedback, by W. Meyer -Eppler. "El.
Rund." Apr. 1956. 3 pp. Based on the method
of Lee, J. Acoust. Soc. America, 1950, the
speaker wears an ear phone and listens to his
own voice. Speech defects are studied. Source
6/6-83
The Electrostatic Loudspeaker Again, "Wirel.
Eng." Mar. 1956. 2 pp. A discussion of the
electrostatic loudspeaker with a charged diaphragm.
It is shown that the main effect of
varying the polarizing voltage is on the L/C
ratio of the resonant branch of the equivalent
circuit. Source 6/6 -84
Physical Sources of Noise, by J. Pierce. "Proc.
IRE" May 1956. 8 pp. A discussion of Johnson
noise and shot noise. Johnson noise is caused
by the fluctuation of charges or polarized molecules
in lossy materials. Shot noise is generated
by a flow of electrons, usually in a vacuum
tube. Source 6/6 -85
Methods of Solving Noise Problems, by W.
Bennett. "Proc. IRE' May 1956. 30 pp. Various
analytical concepts and techniques of
proven value in calculating the response of
electrical systems to noise waves is given.
Relevant probability theory is reviewed with
illustrative examples. It is shown how the
theory can be applied to cases of noise and
signal subjected to such operations as filtering,
rectification, periodic sampling, envelope and
phase detection, and frequency detection.
Source 6/6-86
IRE Standards on Audio Systems and Components:
Methods of Measurement of Gain,
Amplification, Loss, Attenuation, and Amplitude-
Frequency Response, 1956. "Proc. IRE"
May 1956. 19 pp. Methods for making measurements
on systems and components primarily
intended for application or operation at audio
frequencies. The material on each type of
measurement includes a brief discussion of the
principles involved. Source 6/6-87
Synthetic Music, by A. Douglas. "El. Eng."
May 1956. 5 pp. The art of electronic music
has recently been extended to research on the
fundamentals of tone production and the influence
of the non -tonal parameters- noise,
phase -shift, vibrato, etc. -on the sound. From
this work has developed circuits and apparatus
capable of complete synthesis of musical instruments
and the singing voice. Source 6/6 -88
CIRCUITS
Construction and Use of Cathode Follower Design
Charts, by N. Sokal. "El. Des." Apr. 15,
1956. 4 pp. Procedure is given for designing
cathode follower charts for a family of designs
using the same tube and plate supply voltage.
Typical uses are described. Chart may be constructed
for any tube type. Source 6/6-89
Nonlinear Distortion and Stability in Reflex
Circuits, by Yu. A. Chernov. "Radiotek." Jan.
1956. 15 pp. The paper examines the operation
of reflex circuits, taking the nonlinear properties
of the tubes into account. The nonlinear
distortion coefficients are found for the circuits
considered, and new circuits are proposed
which have relatively small nonlinear distortions.
Thorough mathematical analysis is given.
Source 4/6 -90
Wien Bridge Design, by J. Sodaro. "Tele- Tech"
June 1956. 1 p. Nomograph is given which
selects proper values of R and C to give desired
frequency of Wien Bridge. Source 6/6 -239
On the Design of a Discriminator, by E.
Antseliovich. "Radiotek." Jan. 1956. 8 pp. The
paper examines methods for designing discriminators
with tuned and detuned circuits. It is
shown that the region of optimum values for
kQ and AFS /fo practically coincide, both from
the point of view of maximum transfer coefficient
and from the point of view of minimum
nonlinear distortion. Design graphs are given
for the depth of modulation at the input of an
amplitude detector. Source 6/6-91
An Electrostatic Particle Accelerator, by D.
Chick and D. Petrie. "Proc. BIEF" Mar. 1956.
14 pp. A pressurized electrostatic generator
has been designed to give as nearly uniform
as possible field in the dielectric medium, and
the expected performance is calculated assuming
that the insulating gas breaks down at
200 kv /cm. The construction of the generator
and of a multi -section ion accelerator is described,
and the performance of the machine
both as a voltage generator and as an ion
accelerator is described. Source 6/6-92
Designing Cascode Amplifiers with g- Curves,
by K. Pullen, Jr. "El. Des." May 1, 1956. 2 pp.
Conductance curve techniques can be used to
design cascode amplifiers with high amplification
and low noise figure. Design procedures
are given. Source 6/6 -93
A Wide -Range RC Phase -Shift Oscillator, by
W. Fraser. "El. Eng." May 1956. 3 pp. Where
previous circuits of this type have used ac
coupling, it is shown that do coupling may be
used with advantage, and the low frequency
range of the oscillator extended. Two oscillator
circuits and a suitable output stage are given.
Application to polyphase oscillators is also discussed.
Source 6/6 -94
Amplifier Bibliography, by J. Milek and D.
Black. "El. Eq." May 1956. 2 pp. A list of
approximately 25 domestic and foreign books
en all types of amplifiers. Source 6/6-95
A Comparison of the Noise, and Random Frequency
and Amplitude Fluctuations in Different
Types of Oscillator, by R. Beurle. "Proc.
BIEF" Mar. 1956. 8 pp. Noise, present in the
oscillator circuit, even if only that due to
thermal agitation, will appear in the output
circuit, even if steps are taken to stabilize the
output amplitude. The nature of the random
fluctuation in the output is dependent upon the
form of feedback used and the method by
which the output amplitude is controlled. The
author concludes that an oscillator should be
operated at as high a level as possible consistent
with stability of the circuit components.
Source 6/6 -96.
Design of Microwave Filters with Quarter -
Wave Couplings, by G. Craven and L. Lewin.
"Proc. BIEE" Mar. 1956. 5 pp. Resonator diaphrams
are constructed from triplets of inductive
posts, whose spacings and radii are
chosen to prevent the generation of the first 5
non -propagating modes. This is sufficient to
insure negligible coupling at quarter -wave
separation. Measurements on filters at 4000 MC
indicate a satisfactory performance. Source
6/6-97
Transient Phenomena in Band -Pass Amplifiers
with Double -T Sections, by H. Dobesch.
"Hochfreq." Jan. 1956. 6 pp. The responses to
various types of transient inputs of a feedback
amplifier stage having a double -T filter in the
feedback path are derived. The Fourier presentation
is used for the various input voltages
and the Laplace transform method is applied.
Source 6/6 -98
A Receiver for the Radio Waves from Interstellar
Hydrogen. L The Investigation of the
Hydrogen Radiation, by C. Muller. "Phil. Tech."
May 1956. 11 pp. This first of 2 articles outlines
the place of radio astronomy in modern
astronomical research and discusses the nature
and properties of the radiation and the requirements
which the receiver must fulfill. The
second article will give a detailed description
of the receiver circuits. Source 6/6 -225
The Design of Phase -Shift Oscillators and
Filters, by J. Shaw. "El. Eng." May 1956. 3 pp.
Describes a single tube low frequency filter
with a tapered 3 -mesh RC network in a positive
feedback path. Negative feedback provides stability.
Curves are given comparing the attenuation
of the RC network for various input -
output impedance ratios and tapering factors
with those of the equal element case and minimum
attenuation case. Source 6/6 -226
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COMMUNICATIONS
An Extended Analysis of Echo Distortion in
the F. M. Transmission of Frequency -Division
Multiplex, by R. Medhurst and G. Small. "Proc.
BIEE" Mar. 1956. 9 pp. In FM systems, an
important source of intermodulation distortion
is found in the small echoes of the main r -f signal.
By a combination of analytical and semi -
empirical methods, Albersheim and Schafer's
investigations on the distortion due to a single
echo are extended to enable prediction of distortion
levels for most cases of practical interest
in the absence of pre-emphasis). Source
6/6 -99
Facsimile Transmission of Weather Charts and
Other Material by Landline and Radio, by J.
Davidson. "J. BIRE" Mar. 1956. 10 pp. Mechanical
and electrical features of transmitters
and fully automatic recorders designed to meet
the requirements of the Canadian Meteorological
Service are described; specifications are
listed. Facsimile transmission by radio is surveyed.
Machines produced for the transmission
of telegrams and those produced for the transmission
of news -pictures used by the Associated
Press are mentioned. Source 6/6 -100
Facsimile Communication, by H. Woodman and
P. Taylor. "J. BIRE' Mar. 1956. 16 pp. This
survey article includes a description of the
Western Union 100 -line Desk Fax Concentrator,
the Desk -Fax transceiver, the desk -Fax
transmitter and an automatic page recorder.
A general discussion of recording scanners,
recording media, synchronization and transmission
is presented. Source 6/6 -101
Telecommunications in Electric Power Net -
works, by M. Paimboeuf "J. UIT Feb. 1956.
3 pp. Discussion of telephone, telemetering, and
single sideband applications of power line carrier.
Noise and variations in terminal impedance
are discussed. Source 6/6 -256
Automatic Frequency Stabilization for a Beam
Transmitter Working on Centimetric Waves.
by J. Cayzac. "Phil. Tech." May 1956. 6 pp.
An automatic stabilizing device is described
with which the frequency of a beam transmitter,
working with a multi -rebex klystron on
a wavelength of 8.5 cm, can be kept constant
within an accuracy of 1 part in 104. Source
6/6 -102
Beam Transmitters with Double Frequency
Modulation, by C. Ducot. "Phil. Tech." May
1956. 11 pp. This article describes an experimental
beam transmitter and receiver operating
on the principle of double modulation.
With double frequency modulation, the signal
to be transmitted is modulated upon an auxiliary
carrier. The carrier to be transmitted is
then modulated by the auxiliary carrier. The
system is used in carrier -telephony communications.
Source 6/6 -103
130 Tele -Tech & ELECTRONIC INDUSTRIES June 1956