Integrated cable modem

• US 8,578,434 B2
• Filed: 05/20/2005
• Issued: 11/05/2013
• Est. Priority Date: 05/21/2004
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: McMullin, Donald G., Burns, Lawrence M., Dauphinee, Leonard, Gomez, Ramon A., Tan, Loke
• Primary Examiner(s): RABOVIANSKI, JIVKA A
• Application Number:
  US11/133,275
• Publication Number:
  US 20060026659A1
• Time in Patent Office: 3,091 Days
• Field of Search: 725/111, 725/100
• US Class Current: 725/111
• CPC Class Codes: H04N 21/25883 being end-user demographical data, e.g. age, family status or address arrangements for identifying locations of users in broadcast systems H04H60/52
• CPC Class Codes: H04N 21/25891 being end-user preferences retrieval of video data in a video database based on user preferences G06F16/739; arrangements for recognizing users' preferences H04H60/46; user profiles in network data switching protocols H04L67/306; processing of user preferences or user profiles in wireless networks H04W8/18
• CPC Class Codes: H04N 21/4263 involving specific tuning arrangements, e.g. two tuners
• CPC Class Codes: H04N 21/6168 involving cable transmission, e.g. using a cable modem

Abstract

The present invention is an integrated cable modem tuner. In one embodiment, the upstream path and the downstream path are integrated on a common semiconductor substrate. The down-stream path can include a TV tuner and digital receiver portion that is integrated on a common semiconductor substrate with the power amplifier of the upstream path. In another embodiment, the TV tuner is implemented on a first semiconductor substrate and the digital receiver portion and the power amplifier are configured on a second semiconductor substrate. However, the two substrates are mounted on a common carrier so that the cable modem appears to be a single chip configuration to the user.

Claims

1. An integrated cable modem, comprising:

a common substrate;

a down-stream path for down-converting a downstream signal to a down-converted signal, said down-stream path including;

a direct down conversion circuit configured to down-convert said downstream signal to provide a plurality of down-converted components,

a multiplexer configured to interleave said plurality of down-converted components into a single data stream at a first rate,

a single analog-to-digital converter (ADC) configured to convert said single data stream from an analog representation to a digital representation to provide a single digitized intermediate frequency (IF) signal,

a de-multiplexer configured to de-interleave said single digitized IF signal into a plurality of data streams at said first rate, and

a demodulator circuit configured to;

receive said plurality of data streams, and

provide a plurality of digital outputs based on said plurality of data streams; and

an upstream path including a power amplifier for producing an upstream signal, wherein said down-stream path, said ADC, and said upstream path are disposed on said common substrate, and wherein said common substrate is mounted within a semiconductor package.

2. The integrated cable modem of claim 1, wherein said demodulator circuit includes at least one of the following:

a nyquist filter,

a symbol timing circuit,

an equalizer, and

a MPEG decoder.

3. The integrated cable modem of claim 1, wherein said upstream path further includes at least one of the following:

a digital to analog converter,

a media access controller, and

a control circuit.

4. The integrated cable modem of claim 1, wherein said direct down conversion circuit is a quadrature direct down conversion circuit.

5. The integrated cable modem of claim 1, wherein said downstream signal is a quadrature downstream signal, and wherein said direct down conversion circuit comprises:

a first mixer configured to downconvert said quadrature downstream signal based upon a first quadrature local oscillator signal to provide an in-phase component from among said plurality of said down-converted components; and

a second mixer configured to downconvert said quadrature downstream signal based upon a second quadrature local oscillator signal to provide a quadrature phase component from among said plurality of said down-converted components.

6. The integrated cable modem of claim 5, further comprising:

an IQ error detection circuit configured to determine an error of said plurality of down-converted components.

7. The integrated cable modem of claim 6, further comprising:

a local oscillator circuit configured to generate said first quadrature local oscillator signal and said second quadrature local oscillator signal based on an output of said IQ error detection circuit.

8. The integrated cable modem of claim 7, wherein said local oscillator circuit is configured to correct for any IQ phase imbalance determined by said IQ error detection circuit.

9. The integrated cable modem of claim 7, wherein said local oscillator circuit comprises:

a direct digital frequency synthesizer (DDFS) configured to produce a first digital representation of said first quadrature local oscillator signal and second digital representation of said second quadrature local oscillator signal; and

a first and a second digital-to-analog converter (DAC) that is coupled to said DDFS.

10. The integrated cable modem of claim 9, wherein said local oscillator circuit further comprises:

a first and a second low pass filter coupled to an output of said first and said second DAC, respectively; and

a PLL, coupled to said first and said second low pass filter, configured to multiply a frequency of an output of said first and said second low pass filters to produce said first and said second quadrature local oscillator signals, respectively.

11. The integrated cable modem of claim 1, further comprising:

an equalizer, coupled between said single ADC and said demodulator circuit, configured to perform I/Q imbalance correction.

12. The integrated cable modem of claim 11, wherein said equalizer comprises:

a non-decision directed portion configured to receive an output of said single ADC; and

a decision directed portion coupled to an output of said non-decision directed portion.

13. An integrated cable modem, comprising:

a common substrate;

a down-stream path for down-converting a downstream signal to a down-converted signal, said down-stream path including;

a direct down conversion circuit configured to down-convert said downstream signal to provide a plurality of down-converted components including a first down-converted quadrature component and a second down-converted quadrature component,

a multiplexer configured to interleave, at a first rate, first samples of said first down-converted quadrature component and second samples of said second down-converted quadrature component into a single data stream,

a single analog-to-digital converter (ADC) configured to convert said single data stream from an analog representation to a digital representation to provide a single digitized intermediate frequency (IF) signal,

a de-multiplexer configured to de-interleave, at said first rate, said single digitized IF signal into a plurality of quadrature digital signals, and

a demodulator circuit configured to;

receive said plurality of quadrature digital signals, and

provide a plurality of digital outputs based on said plurality of quadrature digital signals; and

an upstream path including a power amplifier for producing an upstream signal, wherein said down-stream path, said ADC, and said upstream path are disposed on said common substrate, and wherein said common substrate is mounted within a semiconductor package.

14. The integrated cable modem of claim 13, wherein said demodulator circuit includes at least one of the following:

a nyquist filter,

a symbol timing circuit,

an equalizer, and

a MPEG decoder.

15. The integrated cable modem of claim 13, wherein said upstream path further includes at least one of the following:

a digital to analog converter,

a media access controller, and

a control circuit.

16. The integrated cable modem of claim 13, further comprising:

an IQ error detection circuit configured to determine an error of said plurality of down-converted components.

17. The integrated cable modem of claim 16, further comprising:

a local oscillator circuit configured to generate a first quadrature local oscillator signal and a second quadrature local oscillator signal based on an output of said IQ error detection circuit.

18. The integrated cable modem of claim 17, wherein said local oscillator circuit is configured to correct for any IQ phase imbalance determined by said IQ error detection circuit.

19. The integrated cable modem of claim 13, further comprising:

an equalizer, coupled between said single ADC and said demodulator circuit, configured to perform I/Q imbalance correction.

20. The integrated cable modem of claim 19, wherein said equalizer comprises:

a non-decision directed portion configured to receive an output of said single ADC; and

a decision directed portion coupled to an output of said non-decision directed portion.