Broadcom Corporation

Gopal Triplicane Venkatesan

Amy Gayle Hundhausen

Hosahalli Rajarao Srinivas

Erik Berg

Thomas J Kolze

Bruce Joseph Currivan

Jonathan S Min

Tak Kwan Lee

Loke Kun Tan

Fang Lu

Kevin Lee Miller

Jeffrey Scott Putnam

Thuji Simon Lin

Ravi Bhaskaran

James P Cavallo

Hsin-An Liu

An integrated digital BTSC encoder with an improved pilot signal generator substantially implemented on a single CMOS integrated circuit. By digitally generating a sinusoid that is frequency locked to a two-state input reference signal using a high rate internal clock, a hardware-efficient BTSC pilot signal generator is provided with good acquisition and tracking performance. Implemented efficiently as a simple phase detector, a low-complexity loop filter, a pilot frequency offset adder, a phase accumulator and a sinusoidal generator, the invention enables lower-rate post-processing of the pilot tone without a costly variable interpolator decimator structures.

BTSC pilot signal lock

An integrated digital BTSC encoder is implemented on a single CMOS integrated circuit chip with an all digital RF modulator. A set top box is provided that allows for a fully integrated solution which may be used with legacy television systems and also with other audio/visual equipment connected to the set top box.

Integrated circuit BTSC encoder

An BTSC encoder with an improved digital filter structure substantially implemented on a single CMOS integrated circuit is described. By cascading first and second order allpass filter structures to form a higher order digital filter, such as a Cauer low pass filter, limit cycle oscillations are reduced or eliminated, word-length growth from one stage to the next is contained, and a more efficient overall filter structure and performance is obtained.

Mechanism for using the allpass decomposition architecture for the cauer low pass filter used in a BTSC

An integrated digital BTSC encoder with an improved pilot signal generator substantially implemented on a single CMOS integrated circuit is described. By digitally generating a sinusoid that is frequency locked to a two-state input reference signal using a high rate internal clock, a hardware-efficient BTSC pilot signal generator is provided with good acquisition and tracking performance. Implemented efficiently as a simple phase detector, a low-complexity loop filter, a pilot frequency offset adder, a phase accumulator and a sinusoidal generator, the invention enables lower-rate post-processing of the pilot tone without a costly variable interpolator decimator structures.

An integrated digital BTSC encoder substantially implemented on a single CMOS integrated circuit is described. By saturating and adding offsets to the value of the feedback control signal in regions of operation where the calculation for the control signal is dominated by noise, an integrated circuit selectively adjusts the control signal for the spectral or wideband feedback loop, as required, so that the performance of a very low noise digital BTSC encoder complies with the requirements of the BTSC standard.

Mechanism for using clamping and offset techniques to adjust the spectral and wideband gains in the feedback loops of a BTSC encoder

All digital reference frequency locking. An all digital approach is provided for operation within one or more CMs within a cable modem communication system to lock the upstream of the one or more CMs to the downstream symbol clock provided from a CMTS. The locking of the CM's upstream may be performed using one of at least three different functions: (1) Locking the upstream symbol clock phase to the downstream symbol clock phase, (2) Locking the downstream symbol clock phase to the headend reference clock phase (typically 10.24 MHz or integer multiple thereof), and (3) Locking the upstream carrier frequency to the downstream symbol clock frequency. The all-digital techniques for supporting all digital reference frequency locking functionality provide high performance to support S-CDMA and other synchronous modulation techniques.

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Aliso Viejo, CA, United States of America

Gopal Triplicane Venkatesan