Average value crossover detector

Claim 2

In combination: delay means responsive to an alternating input signal for delaying said signal; means producing a signal equal to the average value of the delayed and undelayed alternating signal; means storing said average value signal when it is at a fixed value, and comparator means responsive to the signals produced by the delay means and storing means for producing a signal at a first level when the amplitude of the delay means signal exceeds that of the other signal and for producing a signal at a second, different level when the inverse is true.

Claim 3

The combination as set forth in claim 1, wherein the transitions of said alternating signal occur at integral multiples of some value X, and wherein said delay means comprises means for delaying said signal by an amount at least equal to the time required for said alternating signal to transition from one value to another, but not greater than X.

Claim 4

The combination as set forth in claim 1, wherein said means storing said average value signal includes means responsive to said alternating signal for producing a unique pulse when said alternating signal is at a fixed value, and includes one shot signal producing means responsive to the leading edge of said unique pulse for producing a pulse having a terminal point not greater than the time required for a transition in said alternating signal to pass through said delay means, and includes sample and hold means responsive to said pulse from said one-shot for storing said average value signal.

Claim 5

The combination as set forth in claim 1, wherein said means for producing an average value signal includes means for summing said delayed and undelayed signal and includes means responsive to said summed signal for producing a signal which is a fraction of the sum.

Claim 6

The combination as set forth in claim 4, wherein said means producing a fraction of said summed signal produces a signal which is one-half of the sum.

Claim 7

In combination: means producing an alternating signal, the peaks of which may be of non-uniform amplitude; means responsive to said alternating signal for delaying the same; means responsive to said delayed and undelayed alternating signal for producing a signal which is a fraction of the sum of said signals; means responsive to said fraction signal for storing the same when said fraction signal is of fixed value; comparator means responsive to said stored signal and to said delayed signal for producing a signal at a first level when the amplitude of the delay means signal exceeds that of the other signal, and for producing a signal at a second different level when the inverse is true.

Claim 8

In combination: means producing an alternating signal, the peaks of which may be of non-uniform amplitude; means responsive to said alternating signal for delaying the same; means responsive to said delayed and undelayed alternating signal for producing a signal which is a fraction of the sum of said signals; means responsive to said fraction signal for storing the same when said fraction signal is of fixed value; comparator means responsive to said stored signal and to said delayed signal for producing a signal at a first level when the amplitude of the delay means signal exceeds that of the other signal, and for producing a signal at a second different level when the inverse is true.

Claim 9

An arrangement for detecting the times at which an asymmetrical alternating signal changes from a value on one side of a variable threshold level to a value on the other side of this threshold level, where the threshold level is dependent on the varying peak amplitudes of the alternating signal comprising, in combination; means delaying said alternating signal; means responsive to said delayed and undelayed alternating signal for producing a signal having the average value of said signals; means for storing said average value signal produced for a given time interval following the trailing edge of each transition in the alternating signal; means receptive of the delayed alternating signal and stored signal for producing an output signal each time the amplitude level of one of the signals crosses that of the other.

Claim 10

An arrangement for detecting the times at which an asymmetrical alternating signal changes from a value on one side of a variable threshold level to a value on the other side of this threshold level, where the threshold level is dependent on the varying peak amplitudes of the alternating signal comprising, in combination; means delaying said alternating signal; means responsive to said delayed and undelayed alternating signal for producing a signal having the average value of said signals; means for storing said average value signal produced for a given time interval following the trailing edge of each transition in the alternating signal; means receptive of the delayed alternating signal and stored signal for producing an output signal each time the amplitude level of one of the signals crosses that of the other.

Claim 11

The combination as set forth in claim 7, wherein said storing means comprises means responsive to said alternating signal for producing a unique pulse following the end of each transition in said alternating signal, and comprises means responsive to the leading edge of said unique pulse for producing a signal of fixed duration, not in excess of the time required for the alternating signal causing said unique pulse to propagate said delay means, and comprisEs means responsive to the presence of said fixed duration signal for storing said average value signal.

Claim 12

The combination as set forth in claim 7, wherein said average value producing signal means comprises means for summing said delayed and undelayed alternating signals and means for producing a signal which is a fraction of said summed signal, which is said average value signal.

Claim 13

The combination as set forth in claim 9, wherein said means for producing a fraction signal comprises means for producing a signal equal to one-half the summed signal.

Claim 14

Apparatus for reading binary encoded information in the form of alternating regions of indicia, exhibiting two different reflectivities representative of binary information comprising, in combination: optical scanning means producing an alternating signal, the amplitude of which corresponds to the reflectivity of the information being scanned; means for delaying the alternating signal; means producing a signal which is a fraction of the sum of the delayed and undelayed alternating signals; means for storing the fraction signal produced for a fixed time following the trailing edge of each transition in said alternating signal; means receptive of the delayed signal and stored signal for producing an output signal indicative of which of the two received signals is the greater amplitude.

Claim 15

Apparatus for reading binary encoded information in the form of alternating regions of indicia, exhibiting two different reflectivities representative of binary information comprising, in combination: optical scanning means producing an alternating signal, the amplitude of which corresponds to the reflectivity of the information being scanned; means for delaying the alternating signal; means producing a signal which is a fraction of the sum of the delayed and undelayed alternating signals; means for storing the fraction signal produced for a fixed time following the trailing edge of each transition in said alternating signal; means receptive of the delayed signal and stored signal for producing an output signal indicative of which of the two received signals is the greater amplitude.

Claim 16

The combination as set forth in claim 11, wherein said binary encoded information is in the form of regions of two basic colors exhibiting substantially two different reflectivities, the dimension of each region along the scan path being an integral multiple of a unit dimension and wherein said optical scanning means includes means for scanning at a fixed rate along said scan path.

Claim 17

The combination as set forth in claim 12, wherein said delaying means includes means for delaying said alternating signal a time equal to a fraction of the time required to scan said unit dimension.

Claim 18

The combination as set forth in claim 13, wherein said means receptive of said delayed and stored signals includes means for producing a signal at a first level corresponding to a scan of one of said two basic colors when the amplitude of said delayed signal exceeds that of said stored signal and producing a signal at a second level when the reverse conditions are true, the leading edge of each of said levels being delayed from the time of scan across a boundary between said two colors by the amount of delay in said delay means.

Claim 19

Apparatus for reading binary indicia in the form of regions of alternating colors exhibiting two substantially different reflectivities comprising, in combination: optical scanning means producing a signal, the amplitude of which corresponds at any point in time to the reflectivity of the region being scanned, each region along the scan path being greater than a given width; delay means for delaying said optical scanning signal by an amount which is a fraction of the time required by said scanner to scan said given width; means producing a signal which is the average of the signals produced by said optical scanning means and the delayed signal therefrom; means storing said average value signal when it is at a fixed value; means receptive of the delayed signal and stored signal for producing an output signal, the value of which is indicative of which of the two input signals has the greater amplitude, whereby when the stored signal has the greater amplitude, the value of the output signal corresponds to a scan over a region of one reflectivity, while when the delayed signal has the greater amplitude a scan over a region of the other reflectivity is indicated, the leading edge of each value of the signal being delayed from the time of actual scan by the amount of delay in said delay means.

Claim 20

Apparatus for reading binary indicia in the form of regions of alternating colors exhibiting two substantially different reflectivities comprising, in combination: optical scanning means producing a signal, the amplitude of which corresponds at any point in time to the reflectivity of the region being scanned, each region along the scan path being greater than a given width; delay means for delaying said optical scanning signal by an amount which is a fraction of the time required by said scanner to scan said given width; means producing a signal which is the average of the signals produced by said optical scanning means and the delayed signal therefrom; means storing said average value signal when it is at a fixed value; means receptive of the delayed signal and stored signal for producing an output signal, the value of which is indicative of which of the two input signals has the greater amplitude, whereby when the stored signal has the greater amplitude, the value of the output signal corresponds to a scan over a region of one reflectivity, while when the delayed signal has the greater amplitude a scan over a region of the other reflectivity is indicated, the leading edge of each value of the signal being delayed from the time of actual scan by the amount of delay in said delay means.