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US 2004/0164774 A1Published application
Variable-frequency pulse generator
AssigneeMitsubishi Denki Kabushiki Kaisha
InventorYasuhiro Nakashima
Life of this patent
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Abstract
The output (θ2) of a digital adder (13) before being held by a first data holding circuit (14), a first reference value (D1) and a second reference value (D2) are compared, respectively, by a first data comparator (15) and a second data comparator (16), to thereby change one cycle of the output control of the pulse train fout from four cycles (T1-T4) to two cycles (T1-T2) of the reference clock. Further, by comparing the output (θ1) of the first data holding circuit (14) and the first reference value (D1) by a third data comparator (19), the latch timing of the overflow signal is changed from T4 to T1.
Claims4
A variable-frequency pulse generator which executes one cycle of output control of the pulse train by two cycles of a reference clock, comprising:
- an inversion unit which inverts a first reference value regulated by the reference clock;
- a selection unit which selects the first reference value after inversion, when an overflow has occurred, and in any other event selects a predetermined value which changes depending on a set speed;
- a data holding unit which latches an output of a previous stage, being the present value of a result of addition, in the second cycle of the reference clock and at a predetermined timing of an overflow prevention signal;
- an addition unit which adds the value selected by the selection unit and the data latched by the data holding unit;
- a first comparison unit which compares the value obtained by the addition unit as a result of addition and the first reference value;
- a second comparison unit which compares the value obtained by the addition unit as a result of addition and a second reference value which is half of the first reference value;
- a judgment unit which judges whether a condition “0≦addition result<second reference value” is satisfied, or whether a condition “second reference value≦addition result<first reference value” is satisfied, or whether a condition “first reference value≦addition result” is satisfied, and outputs a specified signal corresponding to a result of the judgment;
- a pulse train output unit which latches the specified signal at a predetermined timing of the second cycle of the reference clock, and outputs a pulse train of a desired frequency;
- a third comparison unit which compares the data latched by the data holding unit and the first reference value, and when a condition “latched data≧first reference value” is satisfied, judges that the overflow has occurred;
- and
- an overflow prevention unit which outputs the overflow prevention signal at a predetermined timing of the first cycle of the reference clock, when the third comparison unit has judged that the overflow has occurred.
8 more elements
A variable-frequency pulse generator which executes one cycle of output control of the pulse train by two cycles of a reference clock, comprising:
- an addition unit which adds a predetermined value, which changes depending on a set speed, and data latched at a predetermined timing of the second cycle of the reference clock;
- a subtraction unit which subtracts a first reference value regulated by the reference clock from the value obtained by the addition unit as a result of addition;
- a first comparison unit which compares the value obtained by the addition unit as a result of addition and the first reference value, and when a condition “addition result≧first reference value” is satisfied, judges that an overflow has occurred;
- a second comparison unit which compares the value obtained by the addition unit as a result of addition and a second reference value which is half of the first reference value;
- a selection unit which selects the value obtained by the subtraction unit as a result of subtraction when the overflow has occurred, and in any other event selects the value obtained by the addition unit as a result of addition;
- a data holding unit which latches the value selected by the selection unit at a predetermined timing of the second cycle of the reference clock;
- a judgment unit which judges based on each the results of comparisons in the first comparison unit and the second comparison unit, whether a condition “0≦addition result<second reference value” is satisfied, or whether a condition “second reference value≦addition result<first reference value” is satisfied, or whether a condition “first reference value≦addition result” is satisfied, and outputs a specified signal according to a result of the judgment;
- and
- a pulse train output unit which latches the specified signal at a predetermined timing of the second cycle of the reference clock, and outputs a pulse train of a desired frequency.
6 more elements
A variable-frequency pulse generator which executes one cycle of output control of the pulse train by two cycles of a reference clock, comprising:
- an inversion unit which inverts a reference value regulated by the reference clock;
- a selection unit which selects the reference value after inversion, when an overflow has occurred, and in any other event selects a predetermined value which changes depending on a set speed;
- a data holding unit which latches an output of a previous stage, being the present value of a result of addition, in the second cycle of the reference clock and at a predetermined timing of an overflow prevention signal;
- an addition unit which adds the value selected by the selection unit and the data latched by the data holding unit;
- a first comparison unit which compares the value obtained by the addition unit as a result of addition and the reference value;
- a judgment unit which judges whether a condition “the overflow frequency is an even number” and “0≦addition result<reference value” is satisfied, or whether a condition “the overflow frequency is an even number” and “reference value≦addition result” is satisfied, or whether conditions “the overflow frequency is an odd number” and “0≦addition result<reference value” are satisfied, or whether conditions “the overflow frequency is an odd number” and “reference value≦addition result” are satisfied, and outputs a specified signal corresponding to a result of the judgment;
- a pulse train output unit which latches the specified signal at a predetermined timing of the second cycle of the reference clock, and outputs a pulse train of a desired frequency;
- a second comparison unit which compares the data latched by the data holding unit and the reference value, and when a condition “latched data≧reference value” is satisfied, judges that the overflow has occurred;
- and
- an overflow prevention unit which outputs the overflow prevention signal at a predetermined timing of the first cycle of the reference clock, when the second comparison unit has judged that the overflow has occurred.
7 more elements
A variable-frequency pulse generator which executes one cycle of output control of the pulse train by two cycles of a reference clock, comprising:
- an inversion unit which inverts a first reference value regulated by the reference clock;
- a selection unit which selects the first reference value after inversion, when an overflow has occurred, and in any other event selects a predetermined value which changes depending on a set speed;
- a data holding unit which latches an output of a previous stage, being the present value of a result of addition, in the second cycle of the reference clock and at a predetermined timing of the overflow prevention signal;
- an addition unit which adds the value selected by the selection unit and the data latched by the data holding unit;
- a first comparison unit which compares the value obtained by the addition unit as a result of addition and the first reference value;
- a second comparison unit which compares the value obtained by the addition unit as a result of addition and a second reference value which is half of the first reference value;
- a judgment unit which judges whether a condition “0≦addition result<second reference value” is satisfied, or whether a condition “second reference value≦addition result<first reference value” is satisfied, or whether a condition “first reference value≦addition result<(second reference value×3)” is satisfied, or whether a condition “(second reference value×3)≦addition result” is satisfied, and outputs a specified signal corresponding to a result of the judgment;
- a pulse train output unit which latches the specified signal at a predetermined timing of the second cycle of the reference clock, and outputs a pulse train of a desired frequency;
- a third comparison unit which compares the data latched by the data holding unit and the first reference value, and when a condition “latched data>first reference value” is satisfied, judges that the overflow has occurred;
- and
- an overflow prevention unit which outputs the overflow prevention signal at a predetermined timing of the first cycle of the reference clock, when the third comparison unit has judged that the overflow has occurred.
8 more elements
Dependencies are inferred from the claim text.