Showing papers on "Total harmonic distortion published in 1979"
TL;DR: In this article, the magnetic field strength properties of a typical exciter were examined by experimentally determining the magnetic fields properties of an electrodynamic exciter and the results showed these to be a non-linear even function, which is used with the equations of motion of the excited system.
41 citations
TL;DR: Design of the floating-gate tap structure minimizes code-dependent bias, harmonic distortion, and tap-to-tap nonuniformity, while holding power dissipation to 1 mW per tap.
Abstract: Designs of key sections of a 512-stage correlator are discussed. The chip measures nearly 400 by 300 mils and contains all circuits necessary to accept and store a reference code and compare it to a signal. In addition, it contains many support circuits including the clock logic and drivers, code load logic, and TTL-to-MOS converters. Design of the floating-gate tap structure minimizes code-dependent bias, harmonic distortion, and tap-to-tap nonuniformity, while holding power dissipation to 1 mW per tap. Electron-beam lithography was used to produce photomasks with low defect density and tight dimensional tolerances over the array.
20 citations
Patent•
15 May 1979TL;DR: In this article, a method and apparatus for determining the manner by which an initial injection of wave energy is modified by a medium under test using a time delay spectrometer (TDS) and a fast Fourier transform (FFT).
Abstract: A method and apparatus is disclosed for determining the manner by which an initial injection of wave energy is modified by a medium under test using a time delay spectrometer (TDS) and a fast Fourier transform (FFT). A switch allows either the time delay spectrum or an energy-time curve to be displayed. A differentiator at the input of the FFT corrects for inverse square loss of energy through the medium, i.e., compensates for spherical expansion of energy. Different arrangements of the TDS adapt the system to a medium having variable time delay, or adapt the system for measurement of harmonic distortion through the medium.
20 citations
TL;DR: In this paper, the relative second-and third-harmonic distortion in d.h. semiconductor lasers is investigated and the results are compared to the harmonic distortion predicted from simple rate equations.
Abstract: Experimental investigation of the relative second- and third-harmonic distortion in d.h. semiconductor lasers is presented. The results are compared to the harmonic distortion predicted from simple rate equations. It is suggested that nearfield instabilities limit the minimum distortion level.
11 citations
TL;DR: In this paper, a novel structure for on chip tap weight implementation in CCD transversal filters is described which employs two splits in the CCD sensing electrodes to improve on the performance of the conventional single-split weighting technique.
Abstract: A novel structure for on chip tap weight implementation in CCD transversal filters is described which employs two splits in the CCD sensing electrodes to improve on the performance of the conventional single-split weighting technique. This greatly reduces the capacitance associated with the sensing nodes and consequently reduces the common mode signal, gain sensitivity, coefficient error, and clock noise pickup. Experimental results are presented which verify this improved performance. The results achieved for a 3.4-kHz low-pass filter clocked at 32 kHz show a signal-to-noise ratio of 86 dB with harmonic distortion of less than 0.3 percent.
10 citations
Patent•
26 Nov 1979TL;DR: In this article, a calibration signal source for instruments to measure power and negative sequence current of a multi-phase electric power generator is presented, where separate signals are provided to represent load current for each phase of the generator ultimately to be tested, and to represent the instantaneous differences in voltage between each phase and a reference phase.
Abstract: A calibration signal source for instruments to measure power and negative sequence current of a multi-phase electric power generator. Separate signals are provided to represent load current for each phase of the generator ultimately to be tested, and to represent the instantaneous differences in voltage between each phase and a reference phase. The calibration signals are derived from a single sine wave by providing a plurality of phase shift and voltage difference networks. Means are provided for amplitude control and elimination of harmonic distortion of the single sine wave, and therefore the output calibration signals share these characteristics.
8 citations
TL;DR: The distortion factors which presently limit the dynamic range and usability of transversal filters are described and interaction noise due to rotation of the taps is found to be a major factor.
Abstract: The distortion factors which presently limit the dynamic range and usability of transversal filters are described. In addition to fixed pattern noise and harmonic distortion, interaction noise due to rotation of the taps is found to be a major factor. The dynamic range of the device is analyzed and statistically estimated, with experimental verification.
5 citations
Patent•
13 Sep 1979
TL;DR: In this article, a computer measures distortion factor D from the ratios between the detection output levels of tertiary higher harmonic distortion and 1KHz reproduction levels indicated by the output digital signals of an AD converter 11 at the time of performing the correction while perfoming the correction of recording levels so that the reproduction signal of a tape recorder 1 becomes 0VU.
Abstract: PURPOSE:To automatically set the optimum bias current within a short time by using a computer which operation-controls a variable frequency oscillator and a magnetic recorder-reproducer with a stored program. CONSTITUTION:A computer 2 measures distortion factor D from the ratios between the detection output levels of tertiary higher harmonic distortion and 1KHz reproduction levels indicated by the output digital signals of an AD converter 11 at the time of performing the correction while perfoming the correction of recording levels so that the reproduction signal of a tape recorder 1 becomes 0VU. With the recorder whose distortion factor D exceeds the standard, which of frequency characteristics and distortion factor characteristics is to be preceded has beforehand been determined by a selection switch 3 and therefore this is discriminated. To precede the frequency characteristics, the distortion factor is improved within the range of this standard without changing the standard of the frequency characteristics.
4 citations
Patent•
19 Nov 1979
TL;DR: In this article, the gate electrode of the MOSFET constituting the output stage of the audio output amplifier to the power supply via the diode was connected to improve audio quality.
Abstract: PURPOSE:To reject the harmonic distortion at clip output and to improve audio quality, by connecting the gate electrode of MOSFET constituting the output stage of the audio output amplifier to the power supply via the diode. CONSTITUTION:In the amplifier consisting of the preamplifier 15, differential amplifier consisting of transistors Tr13 and 14, output stage consisting of enhancement MOSFET 18, 19, speaker 5 and negative feedback circuit, each gate of FET's 18 and 19 is connected to the other power supplies 22 and 23 via diodes 20 and 21, and the relation of equations (1) and (2) is given to the power supplies 6, 7 of output stage, preamplifier, each voltage of power supplies 8, 9 of the differential amplifier. Thus, the saturation of Tr12 is avoided with the greater voltage remained than the saturation voltage between the collector and the emitter of Tr12, and the saturation of Tr14 is similarly avoided. Accordingly, even if the signal is clipped, since Tr12 and 14 driving FET 18 and 19 are not saturated, the stepped phenomenon 30 of clip waveform due to storage time lag at saturation is rejected and the harmonic distortion can be reduced.
4 citations
TL;DR: In this article, the dominant cause of even-order harmonic distortion in ac-bias tape recording is a superimposed dc magnetic field in the recording process, and approximate expressions for tape magnetization, playback head flux and equalized playback voltage distortions are derived, taking into account such factors as signal field, dc field, wavelength, tape coating thickness, tape-to-head spacing, playback gap length, record and playback equalization curves.
Abstract: Even-order harmonic distortion in ac-bias tape recording is analyzed. The dominant cause of even-order harmonic generation is a superimposed dc magnetic field in the recording process. Assuming an erf tape magnetization transfer function, approximate expressions for tape magnetization, playback head flux and equalized playback voltage distortions are derived, taking into account such factors as signal field, dc field, wavelength, tape coating thickness, tape-to-head spacing, playback gap length, record and playback equalization curves, etc. The calculated results show excellent quantitative agreement with experimental data.
4 citations
Patent•
02 Feb 1979
TL;DR: In this paper, a distortion factor meter circuit adapted to measure a harmonic distortion factor of a signal, particularly, is presented, where a first transmission line is provided which is adapted to shape a first signal having a harmonic component to produce a DC signal, to convert the DC signal into a square wave having a width proportional to the level of the input DC signal and a predetermined periodicity.
Abstract: This invention relates to a distortion factor meter circuit adapted to measure a harmonic distortion factor of a signal, particularly. A first transmission line is provided which is adapted to shape a first signal having a harmonic component to produce a DC signal, to convert the DC signal into a square wave having a width proportional to the level of the input DC signal and a predetermined periodicity, and thereafter to produce a triangular wave signal having a level linearly increasing from a zero level during the existence of the level of the input square wave signal and linearly decreasing immediately after the level of the square wave signal disappears. A second transmission line is also provided which is adapted to produce a second signal having a residual harmonic component left by eliminating a fundamental from the first signal. Further, a voltage comparator is provided which serves to produce a digital signal of "1" when the level of the output signal from the first transmission line is lower than that from the second transmission line, and to produce a digital signal of "0" when the level of the output signal from the first transmission line is higher than that from the second transmission line. Finally, an integration circuit is provided which serves to integrate the output signal from the voltage comparator.
TL;DR: Advanced analog-binary CCD correlators will be useful in spread spectrum communications and radar systems employing PRN codes and increased code-length capability and on-chip support circuitry drive chip size and density into the VLSI domain.
Abstract: Advanced analog-binary CCD correlators will be useful in spread spectrum communications and radar systems employing PRN codes. Increased code-length capability and on-chip support circuitry drive chip size and density into the VLSI domain. Designs of key sections of a 512-stage correlator are discussed. The chip measures nearly 400 by 300 mils and contains all circuits necessary to accept and store a reference code and compare it to a signal. In addition, it contains many support circuits including the clock logic and drivers, code load logic, and TTL-to-MOS converters. Design of the floating-gate tap structure minimizes code-dependent bias, harmonic distortion, and tap-to-tap nonuniformity, while holding power dissipation to 1 mW per tap. Electron-beam lithography was used to produce photomasks with low defect density and tight dimensional tolerances over the array.
TL;DR: In this paper, the authors show that light signals with very narrow spectra are randomly distorted when transmitted via multimode graded-index fibres, which can be as high as −20 dB after transmission through 1 km of fiber.
Abstract: Light signals with very narrow spectra are randomly distorted when transmitted via multimode graded-index fibres. Detailed experimental results are given for the harmonic distortion, which can be as high as −20 dB, after transmission through 1 km of fibre. The distortion is reduced for laser sources with more longitudinal modes or fibres with higher dispersion.
TL;DR: In this paper, a circuit comprising a digital memory and a d.a. convertor constitutes a cost-effective method of generating data-window waveforms having optimal frequency-domain equiripple sidelobes.
Abstract: A circuit comprising a digital memory and a d.a. convertor constitutes a cost-effective method of generating data-window waveforms having optimal frequency-domain equiripple sidelobes. 8-bit quantisation in the memory and harmonic distortion in the d.a. convertor limit the achievable peak/sidelobe ratio to about 51 dB for the near-in sidelobc, and 54 dB for the far-out sidelobes.
TL;DR: In this paper, square waves generated by a conventional tone generator are applied to a one shot multivibrator, the output of which is a series of narrow rectangular pulses having a flat harmonic spectrum with both even and odd harmonics present.
Abstract: An electronic organ tone generating technique produces a harmonic equivalent of a sawtooth wave. In one embodiment square waves generated by a conventional tone generator are applied to a one shot multivibrator, the output of which is a series of narrow rectangular pulses having a flat harmonic spectrum with both even and odd harmonics present. The narrow rectangular pulses are applied to a 3db per octave filter to produce a waveform, the harmonic content of which is equivalent to that of a sawtooth wave. In this embodiment, the pulse width remains constant regardless of the frequency of the pulse train. In a second embodiment, the duty cycle at each octave when moving up the keyboard is doubled to compensate for amplitude falloff which may occur in the filtered signal.
TL;DR: In this article, the authors describe the operation of the multi-tanh circuit as it applies to triangle-to-sine conversion and present a detailed examination of the properties of the transfer function of the circuit.
Abstract: The paper describes the operation of the multi-tanh circuit as it applies to triangle-to-sine conversion. The treatment includes a detailed examination of the properties of the transfer function of the circuit, an evaluation of total harmonic distortion with circuit parameters chosen to minimise total harmonic distortion.
TL;DR: It is shown that the new approach greatly reduces the capacitance associated with the sensing nodes and consequently reduces the common-mode signal, gain sensitivity, coefficient error, and clock-noise pickup.
Abstract: A novel structure for on-chip tap weight implementation in CCD transversal filters is described. The new approach employs two splits in the CCD sensing electrodes to improve on the performance of the conventional single-split weighting technique. It is shown that the new approach greatly reduces the capacitance associated with the sensing nodes and consequently reduces the common-mode signal, gain sensitivity, coefficient error, and clock-noise pickup. Experimental results are presented which verify the improved performance of the double-split-electrode structure. The results achieved for a 3.4-kHz low-pass filter clocked at 32 kHz show a signal- signal-to-noise ratio of 86 dB with harmonic distortion of less than 0.3 percent.
01 Jan 1979
TL;DR: In this article, the design of a time delay using a CCD as the linear delay element is described, and the design objectives were a timedelay of 160 ms for frequencies up to 14 kHz, and a dynamic range of 40 dB with a minimum signal to noise ratio of 12 dB.
Abstract: The design of a time delay using a CCD as the linear delay element is described. The design objectives were a time delay of 160 ms for frequencies up to 14 kHz, and a dynamic range of 40 dB with a minimum signal to noise ratio of 12 dB. Three different commercial BBD and CCD parts were considered. Among problems addressed are the frequency response and some ways to compensate the severe high frequency attenuation. Harmonic distortion and its complex interaction with the sampling that occurs in the CCD are considered. Quantitative filter requirements for eliminating the harmonics are worked out. Noise problems and temperature effects are also discussed.
01 Jan 1979
TL;DR: In this article, the gate-resistance values can be varied from an effective 1 Gigaohm to 10 kilohms using ion implantation with boron, which predicts high gain at low power and wide dynamic range with low harmonic distortion.
Abstract: Polysilicon resistive-gated MOSFETs are shown to be useful components for linear MOS applications as well as for signal mixers. Gate-resistance values can be varied from an effective 1 Gigaohm to 10 kilohms using ion implantation with boron. Theory for the resistive-gated MOSFET predicts high gain at low power and wide dynamic range with low harmonic distortion. Measurements confirm this theory.
01 Nov 1979
TL;DR: In this article, a three-phase variable-frequency inverter using PWM technique has been designed and constructed in which the notch positions are optimized to eliminate a fixed number of harmonics.
Abstract: A three-phase variable-frequency inverter using PWM technique has been designed and constructed in which the notch positions are optimized to eliminate a fixed number of harmonics. The control circuitry designed to generate optimum notch positions uses digital techniques contrary to analog modulation techniques used in classical PWM which results in less harmonic distortion in the output waveform. The experimental results obtained are in close agreement with the theoretical predictions.
Patent•
27 Jun 1979
TL;DR: In this article, the authors proposed a simple constitution to obtain the circuit which can reduce the high harmonic distortion in the signal through BBD in good manner with simple constitution, where the signal fed to the input terminal 1 is given to the first group BBD1 via the non-inverting bias amplifier A1, and the input signal is entered to the second group CBD2 via the inverting buffer amplifier A2.
Abstract: PURPOSE:To obtain the circuit which can reduce the high harmonic distortion in the signal through BBD in good manner with a simple constitution. CONSTITUTION:The signal fed to the input terminal 1 is given to the first group BBD1 via the non-inverting bias amplifier A1, and the input signal is entered to the second group BBD2 via the inverting buffer amplifier A2. Taking the input signal of BBD of the first and second group as Ecoswt and Ecos(wt+pi), the output signals S1 and S2 include harmonics as equations-(1) and (2). The output signal S1 is given to the non-inverting terminal at the differential amplifier A3 via resistors R1 and R2, and the signal S2 is given to the inverting input terminal of the differential amplifier A3 via the resistor R3. The difference signal S1-S3 as shown in equation-(3) is outputted from the amplifier A3. Thus, since the harmonic components of even order in the output signal at the output terminal 2 is cancelled with the push pull circuit of BBD, the distortion factor can remarkably be improved.