Popular Articles (March 2015)Includes the top 50 most frequently downloaded documents for this publication according to the most recent monthly usage statistics.
A transistor oscillator which is stable up to 150°F has been developed for obtaining electrical measurements. A reactance-modulation technique uses time rather than gain to control the frequency shift. Reactive current of constant amplitude is applied to an L-C circuit for a controlled portion of each cycle. The portion of the cycle is controlled by a bias current injected into the modulating transistor. A differential converter circuit which functions also as a dc amplifier is used with the oscillator in making voltage measurements at high impedance level. Drift of the unit with variation in temperature, vibration, and supply voltage is comparable to that of vacuum-tube multivibrators and dc-amplifier combinations. View full abstract»
The trend among users and builders of automatic digital computing machines is to rely more and more on the computer itself to assist with the compilation of a computing routine. Experience has shown that use of the so-called interpretive subroutines often reduces the overall cost of acquiring a solution to a particular problem. It is also true that, disregarding problem solution time, interpretive subroutines could be written which would permit machines with the most elementary logic (i.e. an instruction list of plus, minus, compare, in, and out) to compare favorably with machines containing an elegant command list. However, though there has been an increased use in computers assembling their own routines, the complement of instructions built into such computers has also been increasing. This is typified by the advent of built-in floating point operations, base registers, etc. Unfortunately the trend of providing more special internal circuitry does not appear to have developed with respect to input-output, wherein negligible increase in machine flexibility other than through programming has been incorporated into newly released computers. View full abstract»
There appears to be a strong reaction among some radio engineers that information theory, or if you prefer, communication theory, is an extremely obtuse and impractical subject useful only as an amusing pastime for mathematicians. Comments are heard much in the same vein as those once made in the aircraft industry about theoretical aerodynemics “It ain't practical, no good will come of it.” View full abstract»
A new FM subcarrier discriminator which utilizes a delay line as the frequency stable element has been developed at the Naval Research Laboratory. When the equipment is used as a telemetering discriminator under field conditions, linearities within 0.25% of full scale can be readily obtained. Theoretically, the linearity is perfect and linearities within 0.1% can be obtained under controlled conditions. No “screwdriver” or tuning adjustments are necessary with the exception of a zero balance in the output voltmeter circuit because the output has been made essentially independent of tube characteristics and component tolerances by the utilization of low power pulse techniques in conjunction with clamping and gating circuitry. The sensitivity is determined by the delay line in combination with a regulated reference voltage. View full abstract»
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This Transactions ceased publication in 1954. The new retitled publication is IEEE Transactions on Aerospace and Electronic Systems.