Circuit for deciding about the position of the repetition frequency of signal transitions in an input signal

Claim 2

A decision circuit which, in response to an input signal in which signal transitions passing through a fixed reference level in a given direction occur at a given repitition frequency, generates a decision signal which is dependent on the position of said repetition frequency relative to a prescribed restricted frequency interval, said decision circuit comprising: signal input means; at least two monostable relaxation generators having different relaxation periods, and respective inputs which are commonly coupled to said signal input means, said relaxation generators changing over to a quasi-stable state at said signal transitions, and providing output pulses having a duration independent of the repetition frequency of said signal transitions; cascade circuit means connected to said monostable relaxation generators, said cascade circuit means comprising smoothing filter means for receiving said output pulses from said relaxation generators, and combination network means connected to said smoothing filter means; and threshold circuit means connected to said combination network means, said threshold circuit means having an output constituting a decision signal output.

Claim 3

A decision circuit which, in response to an input signal in which signal transitions passing through a fixed reference level in a given direction occur at a given repetition frequency, generates a decision signal which is dependent on the position of said repetition frequency relative to a prescribed restricted frequency interval, said decision circuit comprising: signal input means; generators at least two monostable relaxation generatOrs having different relaxation periods, and changing over to a quasistable state at said signal transitions, and providing output pulses having a duration independent of the repetition frequency of said signal transitions; an adjusting circuit connected between the signal input means and said monostable relaxation generators, said adjusting circuit comprising a signal transition detector, and producing a first pulse series by means of signal transition detection by said detector, the pulses of said first pulse series corresponding to said signal transitions, said adjusting circuit also producing a second pulse series whose pulses are shifted in time relative to said first pulse series, and applying both pulse series as a combined series of trigger pulses to at least one of said relaxation generators for controlling the position of at least one of the limits of said prescribed frequency interval; cascade circuit means connected to said monostable relaxation generators; and a threshold circuit connected to said cascade circuit means having an output constituting a decision signal output.

Claim 4

A decision circuit which, in response to an input signal in which signal transitions passing through a fixed reference level in a given direction occur at a given repetition frequency, generates a decision signal which is dependent on the position of said repetition frequency relative to a prescribed restricted frequency interval, said decision circuit comprising: signal input means; generators at least two monostable relaxation generatOrs having different relaxation periods, and changing over to a quasistable state at said signal transitions, and providing output pulses having a duration independent of the repetition frequency of said signal transitions; an adjusting circuit connected between the signal input means and said monostable relaxation generators, said adjusting circuit comprising a signal transition detector, and producing a first pulse series by means of signal transition detection by said detector, the pulses of said first pulse series corresponding to said signal transitions, said adjusting circuit also producing a second pulse series whose pulses are shifted in time relative to said first pulse series, and applying both pulse series as a combined series of trigger pulses to at least one of said relaxation generators for controlling the position of at least one of the limits of said prescribed frequency interval; cascade circuit means connected to said monostable relaxation generators; and a threshold circuit connected to said cascade circuit means having an output constituting a decision signal output.

Claim 5

The decision circuit as claimed in claim 2, wherein said signal transition detector includes a slicer whose decision levels are adjusted at said reference level, and a network connected to said slicer for differentiating an output signal of the slicer.

Claim 6

The decision circuit as claimed in claim 3, wherein a half-wave rec4ifier is connected to an output of said signal transition detector for producing said first series, an output of the half-wave rectifier being connected, both directly and through a delay circuit for producing said second pulse series, to a combination circuit from which said series of trigger pulses is derived.

Claim 7

The decision circuit as claimed in claim 4, wherein said delay circuit comprises a monostable relaxation generator which provides output pulses having a duration determined by its relaxation period, a differentiating network connected to said relaxation generator and a half-wave rectifier which passes to said combination circuit only those output pulses of said differentiating network that coincide with the trailing edges of the output pulses from said relaxatioN generator.

Claim 8

The decision circuit as claimed in claim 5, wherein the connection between the output of said signal transition detector and an input of the relaxation generator which is controlled by said series of trigger pulses includes a full-wave rectifier.

Claim 9

The decision circuit as claimed in wherein the connection between the output of said signal transition detector and an input of a relaxation generator which is controlled exclusively by one of the two pulse series from said series of trigger pulses, includes a half-wave rectifier.