SYSTEM FOR CORRECTING ERRORS IN PULSE DATA

• US 3,845,281 A
• Filed: 02/26/1973
• Issued: 10/29/1974
• Est. Priority Date: 03/01/1972
• Status: Expired due to Term

• Current Assignee: Katumi Iwatani, Kenzi Konisi, Tosio Simizu
• Original Assignee: Katumi Iwatani, Kenzi Konisi, Tosio Simizu
• Inventors: Konisi, Kenzi, Iwatani, Katumi, Simizu, Tosio
• Primary Examiner(s): Shaw, Gareth D.
• Assistant Examiner(s): Gnuse, Robert F.
• Application Number:
  US05/335,817
• Time in Patent Office: 610 Days
• Field of Search: 235/92PL,92CC
• US Class Current: 377/50
• CPC Class Codes: G01C 22/02 by conversion into electric waveforms and subsequent integration, e.g. using tachometer generator G01C22/002, G01C22/004, G01C22/006 take precedence
• CPC Class Codes: G06F 7/62 Performing operations exclusively by counting total number of pulses ; Multiplication, division or derived operations using combined denominational and incremental processing by counters, i.e. without column shift G06F7/68 takes precedence
• CPC Class Codes: G07B 13/02 Details; Accessories

Abstract

A system for correcting errors in pulse data which is capable of correcting the errors by adding correction pulses to or subtracting from input data pulses received within a predetermined period of time. The correction pulses are evenly distributed within the predetermined period of time so as to be added to or subtracted from the data pulses.

Claims

1. A system for correcting errors in the detection of distance travelled by a taxi, the errors being caused by deviation of the diameter of the wheels of the taxi from a standard diameter, comprising:

timing signal producing means for producing first, second and third control signals, a predetermined number of second control signals occurring between successive third control signals, said first control signal being initiated in time coincident with each third control signal, and lasting until the next occurrence of said second control signal;

pulse data input means for producing distance pulses upon rotation of the wheels of the taxi;

first gating means operative in response to said first control signal for converting said distance pulses into timing pulses;

a circulating shift register having an input and an output and comprising a plurality of series-connected bistable elements, wherein said circulating shift register is responsive to said second control signal for storing an accumulated count of said timing pulses, and circulating said accumulated count;

adder means for adding a timing pulse from said first gating means to said accumulated count of timing pulses as said accumulated count is circulated from the output of said circulating shift register, said adder means thereby providing a new accumulated count;

meAns applying said new accumulated count to the input of said circulating shift register;

pulse producing means responsive to said third control signals for producing correction pulses when predetermined counts have been reached in said circulating shift register;

means for selecting at least one of said correction pulses;

means for generating an addition command and a subtraction command; and

correction circuit means responsive to said selected correction pulses and to one of said addition and subtraction commands to alter the application of timing pulses to said adder means, wherein said accumulated count is increased when said addition command is generated, and wherein at least one of said timing pulses is eliminated when said subtraction command is generated.

2. An apparatus of claim 1, wherein said circuit means includes a second gating means responsive to said addition command for passing said distance pulses to said first gating means and responsive to said subtraction command to prevent said distance pulses from reaching said first gating means, a third gating means operative in response to said circuit means for converting one timing pulse to a signal which, when applied to said adder means, increases the accumulated count by at least two, and further includes means for inhibiting said first gating means when said third gating means is operative.

3. An apparatus of claim 1, wherein said pulse producing means includes a plurality of serially connected pairs of bistable elements, each serially connected bistable element having an input and an output, the input of one bistable element in each of said pairs of bistable elements being connected to a predetermined one of said plurality of bistable elements in said circulating shift register, each of said pairs of bistable elements being controlled by said third control signal.

4. An apparatus of claim 3, wherein said selecting includes means generating a selection command, and a plurality of fourth gating means, the output of the other bistable element in each of said pairs of bistable elements being connected to one of said plurality of fourth gating means, said selection command energizing a selected one of said plurality of fourth gating means, each of said plurality of fourth gating means when energized producing a fourth gate pulse having a duration equal to one cycle of said third control signal, and further includes a fifth gating means for passing the fourth gate pulses in the absence of distance pulses.

5. An apparatus of claim 4, wherein said fifth gating means includes a first bistable circuit having set and reset conditions for storing said fourth gate pulses, a second bistable circuit having set and reset conditions adapted to be set by said third control signal when said first bistable means is set and in the absence of distance pulses, and adapted to be reset by said third control signal when said distance pulses are present, and a third bistable circuit having set and reset conditions adapted to be set by said third control signal when said second bistable circuit is set, and adapted to be reset when said distance pulses are absent.

6. An apparatus for correcting errors in the detection of distance travelled by a taxi, wherein detected distance is proportional to the number of revolutions of a taxi wheel, comprising:

pulse generating means for producing distance pulses upon rotation of the taxi wheel, said distance pulses having a pulse rate proportional to the rotational speed of the taxi wheel;

first gating means for converting said distance pulses into first timing pulses;

circulating counter means having an input and output and comprising a plurality of series-connected bistable elements for providing an accumulated count of said first timing pulses;

signal means for circulating said accumulated count from said input to said output at a predetermined rate;

means having first and second inputs for adding each successive first timing pulse from said firSt gating means to the accumulated count;

means for applying said accumulated count to said adding means first input;

means for applying said first timing pulses to said adding means second input;

means for synchronizing the application of the accumulated count and successive first timing pulses to said adding means such that said adding means increases the accumulated count by one for each first timing pulse, thereby providing a new accumulated count;

means for applying said new accumulated count to said input of said circulating counter means;

means responsive to predetermined counts reached in said counter means to generate correction pulses; and

circuit means responsive to said correction pulses to delay one of said first timing pulses sufficiently that the accumulated count is increased by more than one by said adding means.

7. An apparatus of claim 6, wherein said circuit means includes means for generating second timing pulses substantially equal in width to said first timing pulses and synchronized with respect to the application of said accumulated count to the adding means such that the accumulated count is increased by two upon application of said second timing pulse to said adder means, and further includes means for deleting one of said first timing pulses, when one of said second timing pulses is applied to said adder means.

8. An apparatus of claim 6, wherein said synchronizing means includes means for generating a synchronizing signal which is substantially coincident in time with the presence of the least significant digit of said accumulated count at said output of said circulating counter means.

9. An apparatus of claim 6, including means for generating a subtraction command, and wherein said circuit means includes means responsive to said subtraction command and said correction pulses to delete one of said first timing pulses from said first gating means.

10. An apparatus of claim 9, including means for clearing said circulating counter means after a selected accumulated count is reached, and wherein said correction pulse generating means includes means for generating a plurality of sets of correction pulses, each set of correction pulses comprising a plurality of correction pulses separated by a predetermined count of said circulating counter means.

11. An apparatus of claim 10, including means for selecting at least one of said plurality of sets of correction pulses, and means for applying said selected sets of correction pulses to said circuit means, said circuit means generating a second timing pulse in response to each correction pulse, unless said subtraction command is present, said circuit means being responsive to said subtraction command and each correction pulse to delete one first timing pulse.