摘要:

A method for the graphical analysis of various characteristic quantities of active two-port networks, using the Nichols chart, is given. A method of graphically designing high-frequency multistage amplifers using this graphical analysis method is described. The multistage amplifiers can be designed in the same way if any one of three stability factors (invariant stability factor, Stern's stability factor and performance factor) is specified. One can design these amplifiers using only two charts (the Nichols chart and the auxiliary curves overlay) without using many graphs. This method is very convenient in the design of multistage amplifiers using potentially unstable active elements.

DOI:10.1049/ip-g-1.1981.0001

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Development of a hybrid parallel-type correlator is proposed which employs an exponential delta-sigma modulator (e.d.s.m.) coder as an A to D convertor. The use of the e.d.s.m. permits the development of a correlator possessing both the simplicity of the relay-type correlator and the advantages of the Stieltjes-type one. Furthermore, the use of the e.d.s.m. as quantising element permits a wide variation of the delay stepT, which consequently increases the flexibility of the correlator.

DOI:10.1049/ip-g-1.1981.0002

出版商:IEE    

年代:1981

数据来源: IET

摘要:

The measurement of instantaneous spectral energy by the traditional bandpass, rectify and smooth method leaves much to be desired when the signal has a high transient content. The paper presents analytic methods for the designing of ‘phase complementary’ filters based on thetke−atgeneral time window, in both the continuous and discrete time domains. These filters can provide a well-defined measure of instantaneous spectral energy. Digital variants are shown to be capable of computationally efficient practical implementations.

DOI:10.1049/ip-g-1.1981.0003

出版商:IEE    

年代:1981

数据来源: IET

摘要:

A design method for MOS-compatible analogue active filters that use only integrating amplifiers and ratios of capacitors is discussed. The circuits retain most of the implementation advantages of sampled-data switched-capacitor filters, but are complementary to switched-capacitor filters in providing better and more predictable performance at high frequencies. The effects of circuit parasitics and amplifier nonidealities are discussed and experimental results are presented to illustrate the performance.

DOI:10.1049/ip-g-1.1981.0004

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Explict formulas for gain-bandwidth limitations and element values of the Chebyshev and Butterworth bandpass matching networks of two GaAs f.e.t.s in direct cascade are derived. Procedure for gain rolloff compensation using closed-form expressions is also presented. The technique is simple and can be used by nonspecialists without considerable effort.

DOI:10.1049/ip-g-1.1981.0005

出版商:IEE    

年代:1981

数据来源: IET

摘要:

A quick approximate method for hand computation of the coefficients of a Fourier-series model of a nonlinear instantaneous transfer characteristic is presented. The method makes feasible the hand computation of intermodulation product levels of any order, with adequate accuracy for many system design evaluation exercises.

DOI:10.1049/ip-g-1.1981.0006

出版商:IEE    

年代:1981

数据来源: IET

摘要:

Parseval's theorem gives the possibility of connecting the approximation in the time domain in the sense of least squares with the corresponding approximation in the frequency domain. If the poles of the approximating transfer function are known or preassigned (as it can be in the case of activeRC-synthesis) the best location of its zeros can be obtained with the help of the proposed Lagrange-wise ratio. The location of the transfer-function poles can be evaluated, for example, by the decomposition of hyperbolic functions into infinite products; the location of zeros is obtained as the numerator of the above-mentioned ratio at the second stage of the approximation process. The example shows that the combination of these two steps in the frequency domain can give rise to very satisfactory time-domain approximation.

DOI:10.1049/ip-g-1.1981.0007

出版商:IEE    

年代:1981

数据来源: IET

摘要:

By means of straightforward methods, simple approximations are derived for the cosine, sine and tangent functions as well as for their inverse functions. The approximations are simple in the sense that they contain few terms and have numerical coefficients with, at most, three significant figures. The trigonometric approximations presented are valid in all four quadrants, including the singularity points in the case of the tangent. The inverse trigonometric approximations are valid over the full natural argument intervals. The absolute approximation errors are shown to be near-minimax with peak values all less than 0.25% of maximum. The results are expected to be useful in real-time signal processing circuits and systems where speed and simplicity rather than extreme accuracy are the dominating factors. A translinear circuit realisation example is given in the Appendix.

DOI:10.1049/ip-g-1.1981.0008

出版商:IEE    

年代:1981

数据来源: IET

摘要:

GIC-derived second-order active filter sections are known to be ‘optimal’ for a certain choice of element values that preset the filters' signal gain to a fixed value. Further investigations show that, owing to finite amplifier gain-bandwidth products, GIC-derived filters suffer from various deviations, such as severeQ-enhancement, if the gain must be adjustable, so that the optimal low-sensitivity design cannot be implemented. This paper examines this effect and proposes a simple passive compensation technique that requires only a single additional resistor and results in greatly improved GIC-type-filter performance for all gains.

DOI:10.1049/ip-g-1.1981.0009

出版商:IEE    

年代:1981

数据来源: IET