Showing papers on "Ripple published in 1972"

Effect of the magnetic field ripple on diffusion in Tokamaks

Abstract: The magnetic field modulation due to the discrete nature of the field coils in a Tokamak leads to additional particle trapping. The resulting diffusion is evaluated and compared with the neoclassical diffusion. The two diffusion rates are found to be comparable in existing Tokamaks. The limit on the field ripple below which ripple diffusion should be negligible in the next generation of machines is evaluated.

Broad-Band Coupling to High-Q Resonant Loads

Abstract: Broad-band coupling between a resistive source and a resonant load is considered for coupling networks consisting of a uniform transmission line of impedance Z/sub I/ and length equal to a quarter wavelength at the load resonant frequency. An approximate analysis is used to show that either maximally flat or ripple insertion loss frequency response can be obtained by proper choice of Z/sub I/, and the 3-dB bandwidth obtained in either case is always greater than 1/Q. Depending on the ratio of load and source resistances, the bandwidth may be greater than 1 octave. Network design curves for maximally flat operation with a variety of load parameters are computed without approximation. The design of lumped element approximations for the transmission line network is also described.

Hum reduction in transistor amplifiers

Abstract: The low signal hum level in the output of a transistor amplifier is substantially reduced by removing the undesirable ripple voltage normally superimposed on the power supply voltage. A portion of the power supply ripple voltage is capacitively coupled to the emitter electrode of the input transistor stage which provides an out of phase ripple voltage to substantially cancel the ripple voltage appearing at the output terminals.

On maximally flat low-pass filters with ripple in the stopband

Abstract: Maximally flat (MF) low-pass filters of order n with exactly n , or n - 1 finite zeros are investigated and are compared with the same order Butterworth filter, i.e., the MF filter with no finite zeros. It is seen that the MF filter with finite imaginary zeros exhibits sharper cutoff at the edge of the passband and ripple in the stopband. It is shown that the MF filter that maximizes the magnitude of the slope at cutoff is characterized by equal ripple in the stopband. This filter is shown to be the Inverse Chebyshev. Expressions for cutoff slope and for transition bandwidth are derived and are compared with those of the Butterworth filter. The step responses of the Inverse Chebyshev and of the Butterworth are also compared.

Cycloconverter system including means to derive a control signal representing fundamental converter output

Abstract: To permit detection of zero crossing points of the fundamental component of the cycloconverter output current a signal is derived that is the vectorial sum of a current proportional to alternating current in the shunt branch of the cycloconverter output filter and a current proportional to the alternating current in the load. The control signal so developed accurately represents, under steady state as well as transient load conditions, the output current wave of the converter without the characteristic ripple content and is useful for various control functions in cycloconverters.

Design and Maximum Error Estimation for Small Error Low Pass Filters

Abstract: : By using standard spectral windows small error low pass nonrecursive filters may be designed with transition bandwidths inversely proportional to the number of filter weights. The maximum ripple error outside the transition band for any low pass filter using discrete smoothing by the three most standard spectral windows is estimated. Consequently, the straightforward design equations may be used to calculate low pass digital filter weights with a guaranteed maximum error of less than 0.9% or 0.05% depending on how wide the transition band is made. Filters designed in this way have errors comparable to or smaller than those of filters designed by existing techniques and have the advantage that the maximum error is known beforehand.

Automatically terminating battery charging arrangement with means for decreasing ripple effect

Abstract: Charging of a battery from an A.C. source through a controlled rectifier is terminated when a voltage varying directly with the battery output voltage and inversely with A.C. ripple on the battery output voltage has reached a predetermined amplitude.

Synchronous dc power supply

Abstract: A synchronous direct current (dc) power supply has the power supply input drive synchronized with the pulse repetition frequency (PRF) of the amplifying or load circuit requiring the dc power for operation. This limits the occurrence of ripple components in the power supply output to the spectral positions of the PRF lines, eliminating ripple interference with signal processing in the load. An astable multivibrator is synchronized with the PRF generator output frequency. The multivibrator output is converted to a square wave, filtered, and processed to provide a fully rectified output voltage for coupling to the desired load circuit.

Switching voltage regulator circuit

Abstract: A tapped inductor is utilized in a switching mode voltage regulator, which employs a pass transistor and an associated driver transistor connected in a modified Darlington configuration, for the purpose of allowing these transistors to saturate during switching, thereby substantially increasing the over-all efficiency of the regulator. A filter circuit may be added at the output of the voltage regulator to significantly reduce ripple and to improve the response of the regulator to load transients.

Substantially ripple-free fast-response voltage regulated direct-current power supply

Abstract: An alternating-current to direct-current power converter is provided in which alternating-current input is rectified to direct-current and the direct-current voltage is chopped into high frequency alternating current by a free-running, current-limited blocking oscillator. A delay network is provided for squelching high voltage spikes which would otherwise be induced by rate of change of current in transformer inductance. A clamp circuit is provided for holding transformer-generated energy, which is periodically released according to the demands of the power supply. High clamp clamping current-resistance losses are thus avoided.

Oscillator tube filament circuit for high frequency welding generator

Abstract: A high frequency welding apparatus for obtaining consistently high quality welds in metals, particularly those having low magnetic permeabilities and high thermal conductivities. The filament supply to the oscillator tube or tubes of the current generator has been changed from an A-C supply to a D-C supply having a low ripple or no ripple at all. The output stability of the current generator is thereby improved by decreasing the ripple on the output current to less than 6 percent.

Development of Accumulator for High Frequency Ripple Absorption

Abstract: A new accumulator is developed which is possible to absorb ripples by pump and cavitation in valve, ranging from several hundred to several thousand c/sec in the hydraulic system. (Acc: abreviation of Accumulator) The attenuation of Acc in the case of constant flow source and constant pressure source when the pipe is terminated with a throttling load, was computed and compared with experimental values. Observation of the bladders of hat and belows type used in this experiment, was made and by life test, the endurance limit of them was investigated. By improving the bladder's profile and smoothing stress distribution, the author affirmed that this Acc had good endurance limit under ripple pressure of about ±15 kg/cm2.

Frequency response of waveguide filters with thick diaphragms

Abstract: The solution for tho far field diffraction by a slit in a thick conducting screen is utilized to find the scattering coefficients of a symmetric inductive waveguide diaphragm of finite thickness. The resulting equivalent circuit is employed to design a three cavity 0.5 dB pasaband ripple Tehebyseheff filter using thick waveguide diaphragms. The analytical results for the diaphragm and filter are shown to be in good agreement with numerical and experimental data. It is also shown that the diaphragm thickness can be effectively used as an additional design parameter and, with all other parameters fixed, the bandwidth decreases with increasing diaphragm thickness.

Accurate design technique for self-oscillating switching regulators

Abstract: On the basis of simplifying assumptions, equations are derived defining the ripple voltage and operating frequency of the self-oscillating switching regulator in terms of the supply and output voltages, hysteresis voltage, filterchoke inductance, filter capacitance, and a resistance deliberately introduced in series with the filter capacitor. The validity of the equations is checked by testing their predictions against the fundamental differential equations. Design optimisation and limitations are discussed, and an example is given.

Equal capacitor Sallen and Key filters

Abstract: Butterworth and Chebyshev filters are designed using a Sallen and Key structure in which the capacitors are of equal value. Curves of resistor value against amplifier gain are presented, together with a table of design parameters. It is shown that variation of a single resistor can control the Chebyshev realization over a range of pass-band ripple.

Predistorted singly and doubly terminated 0.01 dB-ripple 1st-kind Chebyshev filters

Abstract: Existing synthesis techniques are utilised to develop Tables of low-pass prototype element 'g' values of predistorted singly and doubly terminated first-kind 0.01 dB-ripple Chebyshev-filter networks with up to nine sections. Through conventional frequency-transformation techniques, corresponding bandpass circuits can also be realised. Excessive predistortion (low Q factor) will deteriorate the passband voltage standing-wave ratio, whereas the effects on stopband selectivity are insignificant. Further, the sensitivity of the prototype-element values becomes more acute as the requirement for predistortion is increased. The Tables may be used as a design tool for realising the optimum prescribed insertion-loss characteristics in practical microwave networks where the effects of parasitic component dissipation are critical.