Method and apparatus for providing a circuit with a smooth transfer function
AssigneeRockwell International Corporation
InventorGary F. Hoech
Life of this patent
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Abstract
A circuit for generating a smooth signal for use in linearizing an ARINC specified radio altimeter signal, includes an operational amplifier circuit having a piecewise linear transfer function. A time varying periodic signal is added to the radio altimeter signal at the input of the amplifier circuit, and the signal thus produced is filtered to thereby generate a smooth, linear representation of the altimeter signal. In one embodiment, the smoothed signal is differentiated to generate a signal representing the rate of change of the smoothed, linear signal, or altitude.
Claims13
A circuit for providing a transfer function which accurately approximates a desired smooth transfer function, comprising:
- means for generating a periodic signal,
- means for combining the periodic signal with an input signal,
- means for transforming the combined input and periodic signals, said transforming means having a transfer function which is a segmented approximation of the desired smooth transfer function, and
- means for filtering the periodic signal from the combined and transformed signal, whereby an apparent transfer function approximating the desired smooth transfer function results.
A circuit for smoothly rescaling an input signal, comprising:
- a plurality of amplifiers having inputs to which said input signal is applied, each amplifier being operative over a respective region of said input signal,
- a periodic signal generator,
- means for adding the periodic signal to said input signal at the inputs of said plurality of amplifiers,
- and means for filtering said periodic signal from said output signal, whereby a smoothed, rescaled signal of said input signal is generated.
A circuit for modifying a signal in accordance with a smooth transfer function, comprising:
- (a) a source providing a periodic signal,
- (b) means for adding said periodic signal to said signal to be modified to produce an input signal,
- (c) a circuit having a transfer function represented by a plurality of piecewise linear segments, having an input to which said input signal is applied to produce a transformed output signal, and
- (d) means for filtering said periodic signal from said transformed output.
A circuit for linearizing a signal having linear and logarithmically varying portions, comprising:
- a plurality of operational amplifiers each having an input to which said signal to be linearized is applied,
- said operational amplifiers being biased to each produce a linear output segment over a predetermined range of said signal to be linearized, and having their outputs interconnected to produce a piecewise linear summation signal approximating said signal to be linearized,
- and means for biasing said operational amplifiers into conduction beyond their predetermined ranges to produce a smooth transition between adjacent ranges.
A method for producing a linearly varying signal from a signal having a nonlinearly varying portion, comprising:
- adding a signal having an a.c. component to said signal having a nonlinearly varying portion to produce a summation signal,
- applying said summation signal to a circuit having a piecewise linear segmented transfer function approximating a transfer function required to produce a linear representation of said signal having a logarithmically varying portion,
- and filtering the a.c. component from said summation signal to produce the linear signal.
Dependencies are inferred from the claim text.