Audio amplifier local interface system

• US 20040260416A1
• Filed: 06/10/2004
• Published: 12/23/2004
• Est. Priority Date: 06/10/2003
• Status: Abandoned Application

• Current Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Original Assignee: Harman International Industries Incorporated (Samsung Electronics Co. Ltd.)
• Inventors: Morris, Stephen, Smith, Timothy James, Kellom, Marc, Stanley, Gerald R.
• Application Number:
  US10/866,553
• Publication Number:
  US 20040260416A1
• Time in Patent Office: Days
• US Class Current: 700/94
• CPC Class Codes: H03F 2200/331 Sigma delta modulation being used in an amplifying circuit
• CPC Class Codes: H03F 2203/45138 Two or more differential amplifiers in IC-block form are combined, e.g. measuring amplifiers
• CPC Class Codes: H03F 3/187 in integrated circuits
• CPC Class Codes: H03F 3/45475 using IC blocks as the active amplifying circuit
• CPC Class Codes: H03G 1/02 Remote control of amplification, tone or bandwidth combined with remote tuning or selection of resonant circuits H03J
• CPC Class Codes: H03G 3/002 Control of digital or coded signals H03G3/3089 take precedence
• CPC Class Codes: H04R 5/04 Circuit arrangements, e.g. for selective connection of amplifier inputs/outputs to loudspeakers, for loudspeaker detection, or for adaptation of settings to personal preferences or hearing impairments combinations of amplifiers H03F3/68; stereophonic systems H04S

Abstract

An audio amplifier includes a local interface system and an audio processing system. The local interface system may include a panel mounted display and a user input device. The local interface system may be utilized to locally configure and control the audio amplifier. In addition, when the audio amplifier is connected with a network, the local interface system may be utilized to configure and/or control other network connected devices from the audio amplifier. The audio processing system may process an audio input signal and provide an audio output signal. The audio output signal may be amplified in a power stage that includes a switching amplifier output stage. The audio processing system may dynamically configure the processing to optimize the frequency response of the power stage. The audio processing system may also receive gain commands from the local interface system or over the network to adjust a gain of the audio input signals.

Claims

1. An amplifier for an audio system comprising:

a local interface system that includes a panel mounted display and a user input device;

an audio processing system coupled with the local interface system, the audio processing system configured to be interfaced to a packet switched network to enable access and configuration of other devices coupled with the packet switched network by the local interface system; and

a power stage configured to be controlled and monitored with the audio processing system to produce a plurality of amplified audio output signals.

2. The amplifier of claim 1, where the audio processing system is configurable with one of the local interface system or communication over the packet switched network to process an audio input signal that is provided to the power stage.

3. The amplifier of claim 1, where the audio processing system comprises an audio signal controller, a network interface and a digital signal processor, the digital signal processor configured to receive and process audio signals as directed by the audio signal controller.

4. The amplifier of claim 1, where the local interface system includes an interface controller operable to communicate over an asynchronous serial link with the audio processing system, the audio processing system also configured to communicate over the packet switched network with an Ethernet communication protocol.

5. The amplifier of claim 1, where the audio processing system is configured to monitor a first operational parameter of the amplifier and the local interface system is configured to monitor a second operational parameter of the amplifier.

6. The amplifier of claim 5, where the first and second operational parameters are communicated between the audio processing system and the local interface system over a local communication link.

7. The amplifier of claim 1, where the audio processing system is configured to provide adjustment of the gain applied to an input audio signal based on commands provided by the user interface and the display or provided from the packet switched network to the audio processing system.

8. The amplifier of claim 1, where the power stage comprises a pulse width modulated amplifier output stage.

9. The amplifier of claim 1, where the power stage comprises an output stage that is an opposed current power converter.

10. The amplifier of claim 1, where the panel mounted display is a multiple line character display and the user interface includes a plurality of rotary encoders and a plurality of soft buttons.

12. The amplifier of claim 10, where the audio signal controller is also configured to dynamically adjust the processing of the at least one audio signal by the digital signal processor based on operational parameters provided as inputs to each of the programmable input processor and the local interface system.

13. The amplifier of claim 10, where the audio signal controller is configured to dynamically adjust processing of the at least one audio signal by the digital signal processor based on the output voltage and current of the amplified audio signal.

14. The amplifier of claim 10, where the audio signal controller is configured to dynamically adjust processing by the digital signal processor to optimize the frequency response of the power stage based on comparison of the amplified audio signal to a predetermined amplified audio signal produced from a predetermined audio input signal provided to the digital signal processor by the audio signal controller.

15. The amplifier of claim 10, where the local interface system is enabled to communicate commands over the packet switched network using the audio signal controller to access or configure other devices coupled with the packet switched network.

16. The amplifier of claim 15, where the commands are initiated with the panel mounted display and the user input device.

17. The amplifier of claim 10, where the at least one audio input signal is only one audio input signal and the audio signal controller may selectively configure the digital signal processor to provide the only one audio input signal as a first and a second audio output signal to the power stage.

18. The amplifier of claim 10, where the at least one audio input signal is only one audio input signal and the audio signal controller may selectively configure the digital signal processor to invert the only one audio input signal and provide the only one audio input signal as a first audio output signal to the power stage and provide the inverted only one audio input signal as a second audio output signal to the power stage.

19. The amplifier of claim 10, where the local interface system includes a first security access level and a second security access level, the first security access level is configured to allow access to the audio signal controller over the packet switched network when a user is successfully authenticated by the first security access level, and the second security access level is configured to allow access by the audio signal controller to a subset of control and setup variables that are only present when a user is successfully authenticated by the second security access level.

20. The amplifier of claim 10, where the amplified output signal is in a range of about 1250 watts to about 8000 watts.

11. An amplifier for an audio system comprising:

a power stage having a switching amplifier output stage configured to produce a plurality of amplified audio signals;

a local interface system that includes a panel mounted display and a user input device;

an audio signal controller coupled with the local interface system, the audio signal controller configured to communicate over a packet switched network; and

a digital signal processor coupled with the power stage and in synchronous communication with the audio signal controller, the digital signal processor configured to receive and process at least one audio input signal that is provided to the power stage for amplification;

where the digital signal processor is configured to adjust a gain of the at least one audio input signal based on a gain command to be initiated locally by commands from the local interface system or remotely by commands to be received over the packet switched network.

21. An amplifier for an audio system comprising:

a power stage that includes a switching amplifier output stage, the power stage configured to provide a plurality of amplified audio signals for a load;

an audio processing system configured to receive an audio input signal and provide a processed audio input signal to the power stage for amplification; and

a local interface system coupled with the audio processing system, the local interface system comprising a display and a user interface;

where the audio processing system is configured to dynamically adjust the processing of the audio input signal to optimize the frequency response of the power stage as a function of the amplified audio signals.

22. The amplifier of claim 21, where the display is a multiple line character liquid crystal display and the user interface includes a rotary encoder and a plurality of buttons, the rotary encoder and the buttons each with functionality that is dependent on the contents of the display, the local interface system configured to generate a plurality of screens that include attributes included in each of the screens that are indicative of different functions assigned to each of the buttons.

23. The amplifier of claim 21, further comprising a housing, the power stage, the audio processing system and the local interface system disposed inside the housing, except for the display and user interface that are surface mounted in a front panel of the housing to be accessible to a user.

24. The amplifier of claim 21, where the amplified audio signals are provided as feedback signals to the audio processing system and are communicated to the local interface system over a serial communication link by the audio processing system.

25. The amplifier of claim 21, where the power stage is configured to be controlled and monitored with the combination of the local interface system and the audio processing system.

26. The amplifier of claim 21, where the audio processing system is configured to be engaged in serial communication with the local interface system and also configured to be engaged in Ethernet based communication over a packet switched network.

27. The amplifier of claim 21, where the audio processing system is configured to monitor the amplified audio signals when a predetermined test signal generated by the audio processing system is amplified by the power stage, the output signal to be compared by the audio processing system with a predetermined output signal, and the audio processing system configured to dynamically optimize the frequency response by making frequency based adjustments to the processed audio input signal to correct for response errors.

28. The amplifier of claim 27, where the audio processing system is configured to make frequency based adjustments by filtering the processed audio input signal to adjust the magnitude of the processed audio input signal.

29. The amplifier of claim 21, where the audio processing system comprises an audio signal processor, a digital signal processor and a digital to analog converter, where the audio signal processor is configured to adjust the processing of the digital signal processor, and the audio input signals are processed through the digital signal processor and the digital to analog converter prior to being received at the power stage.

30. The amplifier of claim 29, further comprising a balanced data reconstruction filter, where the digital to analog converter has a balanced output that is provided to the balanced reconstruction filter.

31. The amplifier of claim 21, where the audio processing system is configured to place the amplifier in a standby mode to suspend switching of the switching amplifier output stage based on a standby command received from one of the user interface and the packet switched network.

32. The amplifier of claim 21, where the audio processing system is configured to communicate over a packet switched network using a transmission control protocol.

33. An amplifier for an audio system comprising

a local interface system;

an audio processing system coupled with the local interface system, where the audio processing system is configured to process a balanced audio input signal having a positive channel and a negative channel to provide a balanced audio output signal having a positive channel and a negative channel;

a balanced reconstruction filter that includes a first subfilter configured to filter the positive channel and a second subfilter configured to filter the negative channel of the balanced audio output signal;

a switch mode power stage coupled with balanced reconstruction filter, where the switch mode power stage is configured to receive the balanced audio output signal and generate an amplified audio output signal.

34. The amplifier of claim 33, where the balanced reconstruction filter is configured so that the magnitude of voltage and current of the balanced audio output signal is divided between the first and second subfilters.

35. The amplifier of claim 33, where the audio processing system is configured with a variable gain that is dynamically adjustable by the audio processing system to adjust the magnitude of the balanced audio input signal based on a magnitude of voltage to be supplied to the amplifier.

36. The amplifier of claim 33, where the local interface comprises a display, a rotary encoder and a plurality of buttons, the rotary encoder and the buttons dynamically assigned various functionality dependent on a screen displayed in the display.

37. The amplifier of claim 33, where the audio processing system is configured to provide communication over a packet switched network, the local interface system configured to allow access and control of other devices on the packet switched network.

38. The amplifier of claim 33, further comprising a regulated switch mode power supply with power factor correction capability, the power supply configured to supply regulated power to the local interface system, the audio processing system, the balanced reconstruction filter and the output stage.

39. A method of optimizing the frequency response of an audio amplifier, the method comprising:

supplying a predetermined tuning tone as an audio input signal to a digital signal processor;

processing the predetermined audio input signal with the digital signal processor to generate an audio output signal;

amplifying the audio output signal with a power stage having a switching amplifier output stage switch and an output filter, where the output filter has a frequency dependent output impedance;

an audio signal controller comparing the amplified audio output signal with a predetermined amplified audio output signal; and

the audio signal controller directing dynamic adjustment of the processing by the digital signal processor to optimize the frequency response of the power stage.

40. The method of claim 39, where directing dynamic adjustment of the processing comprises the digital signal processor making frequency dependent magnitude adjustments to the audio input signal being processed by the digital signal processor.

41. The method of claim 39, where directing dynamic adjustment of the processing comprises automatically making changes to the filtering in the digital signal processor with the audio signal controller.

42. The method of claim 39, where comparing the amplified audio output signal comprises comparing the current and voltage magnitude of the amplified audio output signal to a predetermined current and voltage magnitude.

43. The method of claim 39, where comparing the amplified audio output signal comprises identifying response errors between the amplified audio output signal and the predetermined amplified audio output signal.

44. The method of claim 39, where directing dynamic adjustment of the processing comprises optimizing the frequency response of the power stage to be substantially flat.