Integrated modem and line-isolation circuitry with selective modem processing and associated method

• US 6,304,597 B1
• Filed: 01/10/2000
• Issued: 10/16/2001
• Est. Priority Date: 07/23/1999
• Status: Expired due to Term

• Current Assignee: Silicon Laboratories Incorporated
• Original Assignee: Silicon Laboratories Incorporated
• Inventors: Reid, Mitchell, Krone, Andrew W., Dupuis, Timothy J.
• Primary Examiner(s): Pham, Chi
• Assistant Examiner(s): PHU, PHUONG M
• Application Number:
  US09/479,981
• Time in Patent Office: 645 Days
• Field of Search: 375/222, 379/93.05, 379/93.06, 379/93.07, 379/93.08, 379/93.09, 379/93.11, 455/403
• US Class Current: 375/222
• CPC Class Codes: H04L 25/0266 Arrangements for providing Galvanic isolation, e.g. by means of magnetic or capacitive coupling
• CPC Class Codes: H04L 25/4927 using levels matched to the quantisation levels of the channel
• CPC Class Codes: H04L 27/00 Modulated-carrier systems

Abstract

An improved modem architecture and associated method are disclosed that integrate modem functionality and line-side isolation functionality while allowing control of modem processing so that it may be bypassed if raw data, such as raw pulse-code-modulated (PCM) data, is desired to be transmitted or received.

Claims

1. An integrated modem and line-isolation circuit having selective modem processing, comprising:

system-side line-isolation circuitry capable of being coupled to an isolation barrier, the system-side line-isolation circuitry comprising a modem data path for an input data stream that passes through a modem processor and a separate data path for the input data stream that bypasses the modem processor;

digital signal processing (DSP) circuitry integrated with the system-side line-isolation circuitry, the DSP circuitry having a modem processor for the modem data path and a digital processor for system-side circuitry;

selection circuitry coupled to the modem data path and the separate data path; and

a control signal coupled to the selection circuitry, the control signal determining whether data from the modem data path or the separate data path is output from the selection circuitry.

2. The integrated modem and line-isolation circuit of claim 1, wherein the modem processor receives pulse-code-modulated (PCM) data as an input, wherein the separate data path comprises PCM data, and wherein the selection circuitry outputs either modem data from the modem processor or PCM data from the separate data path depending upon the control signal.

3. The integrated modem and line-isolation circuit of claim 2, wherein the PCM data is received across an isolation barrier from a communication line.

4. The integrated modem and line-isolation circuit of claim 1, wherein the modem processor receives modem data as an input and wherein the selection circuitry outputs processed modem data from the modem processor.

5. The integrated modem and line-isolation circuit of claim 4, wherein the processed modem data is transmitted across an isolation barrier to a communication line.

6. The integrated modem and line-isolation circuit of claim 4, wherein the modem data is received from an external system-side integrated circuit.

7. The integrated modem and line-isolation circuit of claim 1, wherein the separate data path comprises pulse-code-modulated (PCM) data and wherein the selection circuitry outputs PCM data.

8. The integrated modem and line-isolation circuit of claim 7, wherein the PCM data is transmitted across an isolation barrier to a communication line.

9. The integrated modem and line-isolation circuit of claim 7, wherein the PCM data is received from an external system-side integrated circuit.

10. The integrated modem and line-isolation circuit of claim 1, further comprising a communication interface capable of connecting to an external system-side integrated circuit.

11. The integrated modem and line-isolation circuit of claim 10, wherein the communication interface is operable as an asynchronous serial interface.

12. The integrated modem and line-isolation circuit of claim 1, wherein the system-side line-isolation circuitry is capable of sending and receiving digital information across the isolation barrier.

13. The integrated modem and line-isolation circuit of claim 12, wherein the digital processor comprises digital filters for digital data received across the isolation barrier from the communication line and a digital modulator for digital data transmitted across the isolation barrier to the communication line.

14. The integrated modem and line-isolation circuit of claim 12, wherein the isolation barrier is a capacitively isolated barrier.

32. The integrated modem and line-isolation circuit of claim 1, wherein the modem processor is configured to support at least one modem communication standard.

33. The integrated modem and line-isolation circuit of claim 32, wherein the modem communication standard comprises V.21, V.22, V.22bis, V.23 or V.25.

15. Digital-signal-processor (DSP) circuitry within an integrated modem and line-isolation circuit having selective modem processing, comprising:

a modem processor;

a modem data path for an input data stream that passes through the modem processor;

a separate data path for the input data stream that bypasses the modem processor;

selection circuitry coupled to the modem data path and the separate data path; and

a control signal coupled to the selection circuitry, the control signal determining whether data from the modem data path or the separate data path is output from the selection circuitry.

16. The DSP circuitry of claim 15, wherein the modem processor receives pulse-code-modulated (PCM) data as an input, wherein the separate data path comprises PCM data, and wherein the selection circuitry outputs either modem data from the modem processor or PCM data from the separate data path depending upon the control signal.

17. The DSP circuitry of claim 15, wherein the modem processor receives modem data as an input and wherein the selection circuitry outputs processed modem data from the modem processor.

18. The DSP circuitry of claim 15, wherein the separate data path comprises pulse-code-modulated (PCM) data and wherein the selection circuitry outputs PCM data.

34. The digital-signal-processor (DSP) circuitry of claim 15, wherein the modem processor is configured to support at least one modem communication standard.

35. The digital-signal-processor (DSP) circuitry of claim 34, wherein the modem communication standard comprises V.21, V.22, V.22bis, V.23 or V.25.

19. A method for selectively utilizing a modem processor in an integrated modem and line-isolation circuit, comprising:

providing a system-side line-isolation integrated circuit capable of being coupled to an isolation barrier, the system-side line-isolation integrated circuit including digital-signal-processing (DSP) circuitry having a modem processor for modem data and a digital processor for system-side circuitry;

further providing within the system-side line-isolation circuitry a modem data path for an input data stream that passes through the modem processor and a separate data path for the input data stream that bypasses the modem processor; and

generating an output for the DSP circuitry by selecting data from the modem data path or from the separate data path.

20. The method of claim 19, wherein the modem processor receives pulse-code-modulated (PCM) data as an input, wherein the separate data path comprises PCM data, and wherein generating step selects either modem data from the modem processor or PCM data from the separate data path.

21. The method of claim 20, wherein the PCM data is received across an isolation barrier from a communication line.

22. The method of claim 19, wherein the modem processor receives modem data as an input and wherein generating step selects processed modem data from the modem processor.

23. The method of claim 22, further comprising sending the processed modem data across an isolation barrier to a communication line.

24. The method of claim 22, further comprising receiving the modem data from an external system-side integrated circuit through an serial interface.

25. The method of claim 24, wherein the serial interface is an asynchronous serial interface.

26. The method of claim 19, wherein the separate data path comprises pulse-code-modulated (PCM) data and wherein the generating step outputs PCM data.

27. The method of claim 26, further comprising sending the PCM data across an isolation barrier to a communication line.

28. The method of claim 26, further comprising receiving the PCM data from an external system-side integrated circuit through the serial interface.

29. The method of claim 28, wherein the serial interface is an asynchronous serial interface.

30. The method of claim 19, further comprising sending and receiving digital information across an isolation barrier.

31. The method of claim 30, wherein the isolation barrier is a capacitively isolated barrier.

36. The method of claim 19, wherein the modem processor is configured to support at least one modem communication standard.

37. The method of claim 36, wherein the modem communication standard comprises V.21, V.22, V.22bis, V.23 or V.25.