Data receiver capable of invalidating erroneous pulses

• US 20020084841A1
• Filed: 12/05/2001
• Published: 07/04/2002
• Est. Priority Date: 12/28/2000
• Status: Active Grant

• Current Assignee: DENSO Corporation
• Original Assignee: DENSO Corporation
• Inventors: Taguchi, Akihiro, Tsuji, Hiroyuki
• Granted Patent: US 6,633,620 B2
• Time in Patent Office: Days
• US Class Current: 329/312
• CPC Class Codes: B60C 23/0408 transmitting the signals by non-mechanical means from the wheel or tyre to a vehicle body mounted receiver
• CPC Class Codes: B60C 23/0462 Structure of transmission protocol
• CPC Class Codes: H03K 5/1252 Suppression or limitation of noise or interference specially adapted for transmission systems H04B15/00, H04L25/08
• CPC Class Codes: H04L 1/246 two-level transmission codes, e.g. binary
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation

Abstract

In a data receiver, pulse edges are sequentially detected from the pulse string. If a pulse which has a width equal to two cycles of the reference clock signals is detected, bit data ‘1’ is restored. If two consecutive pulses each of which has a width equal to one cycle are detected, bit data ‘0’ is restored. If a pulse width between two consecutive pulse edges is not equal to one cycle or two cycles, it is presumed that a pulse edge of an erroneous pulse is detected. If the pulse width between the pulse edge, which is presumed to correspond to the erroneous pulse, and the next pulse edge is equal to or shorter than a predetermined threshold Th, the pulse edge and the next pulse edge is invalidated.

Claims

1. A data receiver comprising:

receiver means for receiving a pulse string in which each bit of binary data is represented by a pulse width between two consecutive pulse edges synchronized with regular reference clock signals;

edge detection means for sequentially detecting a pulse edge from said pulse string;

determination means for determining whether a pulse width between the preceding pulse edge and the present pulse edge is synchronized with the reference clock signals when the present pulse edge is newly detected by said edge detection means;

edge invalidation means for invalidating the present pulse edge so that the present pulse edge is not inputted to said determination means when said pulse width is shorter than one cycle of reference clock signals; and

data restore means for restoring said binary data by determining each bit of said binary data based on said pulse width when said determination means determines that said pulse width is synchronized with the reference clock signals,

wherein, when said determination means determines that said pulse width is not synchronized with the reference clock signals, it is determined that a receipt error occurs, and data restore operation by said data restore means is stopped.

2. A data receiver as in claim 1,

wherein said edge invalidation means is activated only when a time elapsed after said data restore means newly determines one bit of said binary data is shorter than one cycle of the reference signals.

3. A data receiver as in claim 1,

wherein said edge invalidation means comprises pulse width detection means which detects a pulse width between the present pulse edge and a next pulse edge when said pulse width between the preceding pulse edge and the present pulse edge is shorter than one cycle of the reference signals, and

wherein, when the pulse width detected by said pulse width detection means is equal to or shorter than a predetermined threshold which is shorter than one cycle of the reference signals, said invalidation means invalidates the present pulse edge and the next pulse edge so that the present pulse edge and the next pulse edge are not inputted to said determination means.

4. A data receiver as in claim 3,

wherein, when the pulse width detected by said pulse width detection means is longer than said predetermined threshold, it is determined that a receipt error occurs, and data restore operation by said data restore means is stopped.

5. A data receiver as in claim 1,

wherein, if the pulse width between the preceding pulse edge and the present pulse edge is longer than one cycle of the reference signals but shorter than two cycle of the reference signals, edge invalidation means invalidates the present pulse edge so that the present pulse edge is not inputted to said determination means.

6. A data receiver for restoring binary data from a pulse string comprising:

receiver means for receiving a pulse string in which each bit of the binary data is represented by a pulse width between two consecutive pulse edges synchronized with regular reference clock signals;

edge detection means for sequentially detecting a pulse edge from said pulse string;

determination means for determining whether a first pulse width between first two consecutive pulse edges coincides with one of valid pulse widths which represent a bit of the binary data;

data restore means for restoring the binary data by determining each bit of the binary data based on the first pulse width if said determination means determines that the first pulse width coincides with one of the valid pulse widths;

edge invalidation means for invalidating latter of second two consecutive pulse-edges so that said determination means ignores the latter of the second consecutive pulse edges if it is determined that a second pulse width between the second consecutive pulse edges exceeds a predetermined threshold shorter than one cycle of the reference signals and does not coincide with one of the valid pulse widths and a third pulse width between former of the second consecutive pulse edges and a previous pulse edge, which is detected by said edge detection means immediately before the former of the second consecutive pulse edges and is not invalidated by said edge invalidation means, coincides with one of the valid pulse widths; and

restore stop means for stopping the restoration of the binary data if said determination means determines that the first pulse width does not coincide with one of the valid pulse widths.

7. A data receiver as in claim 6,

wherein said edge invalidation means is activated only when a time elapsed after a pulse edge, which is not invalidated by said edge invalidation means, is detected by said edge detection means is shorter than one cycle of the reference clock signals.

8. A data receiver as in claim 6,

wherein, when it is determined that the second pulse width exceeds the predetermined threshold and does not coincide with one of the valid pulse widths and the third pulse width coincides with one of the valid pulse widths, said edge invalidation means invalidates both of the latter of the second consecutive edges and a next pulse edge which is detected by said edge detection means immediately after the latter of the second consecutive pulse edges if it is determined a pulse width between the latter of the second consecutive pulse edges and the next pulse edge is equal to or shorter than the predetermined threshold.

9. A method for restoring binary data from a pulse string in which each bit of the binary data is represented by a pulse width between two consecutive pulse edges synchronized with regular reference clock signals, the method comprising the steps of:

detecting a pulse edge sequentially from the pulse string;

determining whether a first pulse width between first two consecutive pulse edges coincides with one of valid pulse widths which represent a bit of the binary data;

restoring the binary data by determining each bit of the binary data based on the first pulse width if it is determined that the first pulse width coincides with one of the valid pulse widths at said determining step;

invalidating latter of second two consecutive pulse edges so that the latter of the second consecutive pulse edges is ignored at said determining step if it is determined that a second pulse width between the second consecutive pulse edges exceeds a predetermined threshold shorter than one cycle of the reference signals and does not coincide with one of the valid pulse widths and a third pulse width between former of the second consecutive pulse edges and a previous pulse edge, which is detected at said detecting step immediately before the former of the second consecutive pulse edges and is not invalidated at said invalidating step, coincides with one of the valid pulse widths; and

stopping the restoration of the binary data if it is determined that the first pulse width does not coincide with one of the valid pulse widths at said determining step.

10. A method as in claim 9,

wherein said invalidating step is performed only when a time elapsed after a pulse edge, which is not invalidated at said invalidating step, is detected at said detecting step is shorter than one cycle of the reference clock signals.

11. A method as in claim 9,

wherein, when it is determined that the second pulse width exceeds the predetermined threshold and does not coincide with one of the valid pulse widths and the third pulse width coincides with one of the valid widths, both of latter of the second consecutive edges and a next pulse edge, which is detected at said detecting step immediately after the latter of the second consecutive pulse edges, are invalidated at said invalidating step if it is determined a pulse width between the latter of the second consecutive pulse edges and the next pulse edge is equal to or shorter than the predetermined threshold.

12. A tire condition monitoring system for monitoring an air pressure in tires of a vehicle, comprising:

transmitter means incorporated in the tires for generating a signal by modulating a predetermined carrier wave using a pulse string in which each bit of binary data that represents the air pressure in the tires is represented by a pulse width between two consecutive pulse edges synchronized with regular reference clock signals, said transmitter means transmitting the generated signal; and

a data receiver for receiving the signal from said transmitter means and restoring said binary data from said received signal, said data receiver comprising;

receiver means for demodulating the received signal so that said pulse string is extracted;

edge detection means for sequentially detecting a pulse edge from said pulse string;

determination means for determining whether a pulse width between the preceding pulse edge and the present pulse edge is synchronized with reference clock signals when the present pulse edge is newly detected by said edge detection means; and

data restore means for restoring said binary data by determining each bit of said binary data based on said pulse width when said determination means determines that said pulse width is synchronized with the reference clock signal,

wherein, when said determination means determines that said pulse width is not synchronized with the reference clock signals, it is determined that an receipt error occurs, and data restore operation by said data restore means is stopped, and

wherein said data receiver further comprises edge invalidation means for invalidating the present pulse edge so that the present pulse edge is not inputted to said determination means when said pulse width is shorter than one cycle of reference clock signals.