Method and apparatus for pulse position modulation

• US 6,212,230 B1
• Filed: 04/04/1998
• Issued: 04/03/2001
• Est. Priority Date: 04/04/1998
• Status: Expired due to Term

• Current Assignee: NXP USA, Inc. (NXP Semiconductors NV)
• Original Assignee: SigmaTel Incorporated (NXP Semiconductors NV)
• Inventors: Markison, Timothy W., Margules, Michael A., Kodra, Gregg S., Rybicki, Mathew A., Jackson, H. Spence
• Primary Examiner(s): Chin, Stephen
• Assistant Examiner(s): DEPPE, BETSY LEE
• Application Number:
  US09/071,239
• Time in Patent Office: 1,095 Days
• Field of Search: 375/239, 375/238, 375/284, 375/353, 332/108, 332/109, 332/112, 332/115, 370/205, 370/212, 370/213, 370/533, 327/172, 327/178, 327/306, 341/50, 341/52, 341/53, 341/173, 341/182
• US Class Current: 375/239
• CPC Class Codes: G11B 20/10 Digital recording or reproducing
• CPC Class Codes: G11B 20/10527 Audio or video recording; Data buffering arrangements G11B20/12 - G11B20/18 take precedence
• CPC Class Codes: H03K 7/04 Position modulation, i.e. PPM
• CPC Class Codes: H04B 14/026 using pulse time characteristics modulation, e.g. width, position, interval
• CPC Class Codes: H04L 25/4902 Pulse width modulation; Pulse position modulation

Abstract

A method and apparatus for pulse position modulation begins when a digital data stream is received. The encoding process continues by obtaining a set of bits from the digital data stream and modulating the set of bits into a pulse having a pulse width. Next, a transition edge of the pulse is positioned at one of a plurality of time intervals within a time chip based on the set of bits, wherein the pulse width is greater than each of the plurality of time intervals.

Claims

1. A method for pulse position modulation, the method comprising the steps of:

(a) receiving a digital data stream;

(b) obtaining a set of bits from the digital data stream;

(c) modulating the set of bits into a pulse having a first pulse width when the set of bits are in a first range of values and modulating the set of bits into the pulse having a second pulse width when the set of bits are in a second range of values;

(d) based on the set of bits, positioning a transition edge of the pulse at one of a plurality of time intervals within a time chip, wherein the first pulse width and the second pulse width are greater than any one of the plurality of time intervals.

2. The method of claim 1 further comprises:

obtaining a second set of bits from the digital data stream;

modulating the second set of bits into a second pulse; and

positioning a transition edge of the second pulse at one of a plurality of time intervals of another time chip.

3. The method of claim 1 further comprises, within step (d), positioning the pulse at at least one of a leading transition edge and a trailing transition edge of one of the plurality of time intervals.

4. The method of claim 1 further comprises modulating an amplitude of the pulse based on the set of bits.

5. The method of claim 1 further comprises, within step (c), modulating the set of bits into the pulse having a third pulse width when the set of bits are in a third range of values.

6. A method for pulse position modulating, the method comprising the steps of:

a) receiving a digital data stream;

b) obtaining a set of bits from the digital data stream;

c) positioning a pulse at one of a plurality of time intervals to represent the set of bits, wherein the pulse has a first pulse width when the set of bits are in a first range of values and the pulse has a second pulse width when the set of bits are in a second range of values.

7. The method of claim 6 further comprises modulating an amplitude of the pulse to further represent the set of bits.

8. The method of claim 6 further comprises, within step (c), generating the pulse to have a third pulse width when the set of bits are in a third range of values.

9. A pulse position modulator comprising:

a data receiver operably coupled to receive a digital data stream and to provide, at predetermined intervals, a set of bits from the digital data stream;

a pulse generation circuit operably coupled to generate the pulse to have a first pulse width when the set of bits are in a first range of values and to generate the pulse to have a second pulse width when the set of bits are in a second range of values;

a pulse positioning circuit operably coupled to the data receiver and pulse generation circuit, wherein, based on the set of bits, the pulse positioning circuit positions the pulse at one of a plurality of time intervals of a time chip, wherein the the first pulse width and the second pulse width are greater than any one of the plurality of time intervals.

10. The pulse position modulator of claim 9, further comprises the pulse generation circuit being operably coupled to generate the pulse to have a third pulse width when the set of bits are in a third range of values.

11. The pulse position modulator of claim 9 further comprises the pulse generation circuit being operably coupled to generate the pulse having a first amplitude when the set of bits are in a first range of values and to generate the pulse having a second amplitude when the set of bits are in a second range of values.

12. The pulse position modulator of claim 9 further comprises a driver operably coupled to the pulse positioning circuit, wherein the driver amplifies the positioned pulse.

13. The pulse position modulator of claim 12, further comprises a light transmitting diode operably coupled to the driver, wherein the light transmitting diode transmits, via an infrared transmission path, the amplified pulse.

14. The pulse position modulator of claim 9 further comprises memory operably coupled to the positioning circuit, wherein the memory stores a look-up table that relates the set of bits to particular ones of the plurality of intervals.

15. A pulse position modulator comprises:

a processing device; and

a memory that stores programming instructions that, when read by the processing device, causes the processing device to (a) receive a digital data stream;

(b) obtain a set of bits from the digital data stream;

(c) modulate the set of bits into the pulse having a first pulse width when the set of bits are in a first range of values and modulate the set of bits into the pulse having a second pulse width when the set of bits are in a second range of values; and

(d) based on the set of bits, position a transition edge of the pulse at one of a plurality of time intervals within a time chip, wherein the first pulse width and the second pulse width are greater than any one of the plurality of time intervals.

16. The pulse positioning modulator of claim 15 further comprises, within the memory, programming instructions that, when read by the processing device, causes the processing device to modulate an amplitude of the pulse based on the set of bits.

17. A pulse position modulator comprises:

a processing device; and

a memory that stores programming instructions that, when read by the processing device, causes the processing device to (a) receive a digital data stream;

(b) obtain a set of bits from the digital data stream; and

(c) based on the set of bits, position a transition edge of the pulse at one of a plurality of time intervals within a time chip, wherein the pulse has a first pulse width when the set of bits are in a first range of values and a second pulse width when the set of bits are in a second range of values the first pulse width and the second pulse width being greater than any one of the plurality of time intervals.

18. The pulse positioning modulator of claim 17 further comprises, within the memory, programming instructions that, when read by the processing device, causes the processing device to modulate an amplitude of the pulse to further represent an individual value.