Scanning means

Claim 3

The method of claim 1 wherein the storage of the signal amplitude value is continued at least until the end of the next succeeding signal amplitude value.

Claim 4

The method of claim 1 wherein the signal amplitude values are fed to a minimum value store and a maximum value store having storage contents which at each signal transition are approximated to each other by a predetermined amount which is adjusted relative to the difference between the storage contents.

Claim 5

The method of claim 3 wherein an approximation is carried out for a time adjusted according to said predetermined relative amount using a time constant which at most is equal to the shortest expected duration of a Signal transition.

Claim 6

The method of claim 3 for the evaluation of bivalent signal sequences, preceded each time by a signal pattern having essentially constant signal amplitude, wherein during each such preceding signal pattern the contents of the maximum value store and of the minimum value store are made to approach one another with a time constant which is larger than the longest expected duration of the signal transition following said preceding signal pattern and having a considerably smaller time constant than the shortest expected preceding signal pattern, and effecting a reduction of the effective storage content of the minimum value store in the direction of the signal transition occurring at the start of the preceding signal pattern.

Claim 7

The method of claim 1 wherein the stored signal amplitude value is modified by a predetermined amount in the direction of the first-named signal transition before generating said mean value.

Claim 8

The method of claim 6 wherein the traversing of the controlled threshold value by the signal during a signal transition is employed as the criterion for determinging the beginning of the modification of the respective stored signal amplitude value.

Claim 9

Signal processing apparatus for generating a pulse sequence signal of constant pulse amplitude from a bivalent signal having transitions between a maximum and a minimum amplitude values and having a superimposed unidirectional time-varying component, said apparatus comprising an input amplifier to which the bivalent signal is fed, a comparator having one input fed from said amplifier and a reference input fed from a mean value circuit, stores for storing maximum and minimum values of said signal, a mean value circuit for producing a mean value from the contents of the stores and an approximating circuit adapted to influence said stores, said approximation circuit being activated for appropriate periods of time by signal transitions accuring at the output of said comparator and being adapted to produce a predetermined degree of approximation.

Claim 10

Signal processing apparatus for generating a pulse sequence signal of constant pulse amplitude from a bivalent signal having transitions between a maximum and a minimum amplitude values and having a superimposed unidirectional time-varying component, said apparatus comprising an input amplifier to which the bivalent signal is fed, a comparator having one input fed from said amplifier and a reference input fed from a mean value circuit, stores for storing maximum and minimum values of said signal, a mean value circuit for producing a mean value from the contents of the stores and an approximating circuit adapted to influence said stores, said approximation circuit being activated for appropriate periods of time by signal transitions accuring at the output of said comparator and being adapted to produce a predetermined degree of approximation.

Claim 11

The apparatus of claim 21 further comprising a control loop leading from the comparator output to the input of the amplifier and including a control value store and a normally closed switching device for opening and closing the loop, said switching device being opened by a bistable circuit actuated by the appearance of a first predetermined signal amplitude value in said store for storing said maximum value.

Claim 12

The apparatus of claim 9 further comprising a regulating circuit controlled by said bistable circuit and by the generated pulse train produced by said apparatus said regulating circuit being adapted to switch at the start of a signal pattern having an essentially constant signal amplitude the approximation circuit from a small time constant to a large time constant simultaneously with an attentuation circuit which is coupled to the output side of said store for storing said minimum value.

Claim 13

The apparatus of claim 9 wherein the reference input of the comparator is connected through an additional switching device controllable by said bistable circuit for applying a zero potential.

Claim 14

The apparatus of claim 11, further comprising means for generating a normalizing signal at the end of the signal sequence which is fed to the resetting input of the bistable circuit.

Claim 15

The apparatus of claim 8 wherein the output of the input amplifier is connected to a control circuit, said control circuit being adapted to generate a signal influencing the gain of the input amplifier as a function of the amplitude of the signal at the output of said amplifier.

Claim 16

The apparatus of claim 13 wherein the output of said amplifier is connected to the input terminal through a variable resistance value which is controlled by the signal generated by said control circuit.

Claim 17

The apparatus of claim 14 wherein said variable resistance is a field effect transistor.

Claim 18

The apparatus of claim 13 wherein said control circuit has an outPut coupled to a holding circuit for maintaining the control signal influencing the gain of the amplifier to proximate its initial value in the course of a measuring phase.

Claim 19

The apparatus of claim 13 wherein said control circuit comprises a comparator having a input and adapted to generate a signal reducing the gain of the input amplifier when a predetermined signal value at the output of said amplifier is exceeded.