MCNS-Compliant, Physical-Layer Upstream/Downstream Devices for Cable Modems, Set-Top Boxes, and More.

BRISBANE, Calif.--(BUSINESS WIRE)--March 23, 1998--

Fully-digital ICs simplify systems, help prevent data loss due to

transmission problems, and outperform mixed-signal devices

By measuring and modeling the performance of cable TV networks, then developing and implementing digital ICs dedicated to reducing errors caused by common transmission problems, Hitachi Semiconductor (America) Inc. has produced two fundamental building blocks for cable modems, digital set-top boxes, and other products (such as PCs) that now connect to digital cable systems or will do so in the future. The totally digital chips-the HD49430F downstream processor and the HD49429F upstream processor-are 100% compliant to MCNS (Multimedia Cable Network Standard) for compatibility and easy system integration. The devices can be used individually or as a pair, depending on requirements.

To help ensure network subscriber quality of service within hostile cable environments, the chips offer significant system design and performance advantages compared to conventional analog and mixed-signal solutions. Their architectures are designed to help keep overall system cost low.

An All-Digital Solution that Performs Better and Requires Fewer Components

According to Jim Shupenis, Product Manager at Hitachi Semiconductor (America) Inc., "Hitachi is committed to providing digital solutions that allow OEMs to produce cost-effective products that give people the easiest, most convenient access to reliable communication and information services worldwide. Digital technology is the key here. It inevitably prevails over analog or mixed-signal technology because it permits higher levels of integration and therefore lower costs. When digital techniques are innovatively applied to their fullest potential, they provide superior performance to analog and mixed-signal designs, while eliminating sources of drift and error with temperature and time.

"The new HD49430F is a breakthrough. It tolerates high levels of channel impairments and is forgiving of "consumer-grade" tuners in both in 256 and 64 Quadrature Amplitude Modulation (QAM) modes. The chip requires less complex external circuitry and doesn't need complex analog control loops for carrier recovery and timing recovery. Those functions are performed entirely on chip using patented signal processing techniques. Because all of the processor's feedback loops are digital-including automatic gain control (AGC), symbol timing recovery, and carrier recovery-response is rapid and control is tight.

"The chip's high phase-noise tolerance permits the use of economical, consumer-grade tuners without data loss. Also, the chip produces a very low bit error rate (BER), even under conditions of severe channel impairments and inexpensive tuners."

Downstream Processor Can Compensate for Network Signal Conditions

In addition to a high-performance 256/64 QAM demodulator and a MCNS-compliant forward error correction (FEC) decoder(a), the HD49430F downstream processor contains on-chip registers and interfaces (a general-purpose JP port and a serial I2C port) that permit monitoring of the status of the IC and the signal conditions on the network. Those registers and interfaces also allow the chip's signal processing parameters to be programmed to settings other than the default settings.

This extra circuitry can provide important application advantages. For example, in the set-top box at the subscriber site, the HD49430F can be connected to a microprocessor to enable the network service provider to measure cable operating conditions at that site automatically, and even remotely, for channel monitoring. Should the signal output from the box be degraded by network conditions, some operations of the HD49430F's internal processing functions (equalizer, carrier acquisition, interference canceling, among others) can be reprogrammed to correct the impaired network signal, thereby maximizing the quality of the signal from the box to achieve the most efficient data transmission and the optimum picture and sound. Software is also available from Hitachi that permits the HD49430F to re-configure its signal processing parameters automatically, using a form of "expert system" control, in cases of unusual channel conditions.

The signal processing flexibility allowed by the HD49430F's programmability probably won't be used in low-cost systems. For basic implementations, the downstream processor provides full capability in stand-alone operation without external MPU support. All of the chip's performance specifications are given at default settings.

Accepts 8-bit or 10-bit Input Sampling; Gives High Noise Immunity

When used with 6-MHz channels, the highly integrated, fully digital HD49430F downstream processor implements 40-Mb/s (256 QAM) and 30-Mb/s (64 QAM) data rates. The 3.3-V device works with 8-bit or 10-bit input sampling and provides high noise immunity. An on-chip tone canceller removes narrowband interference for improved carrier lock, and special signal processing algorithms handle impulse noise that might otherwise disrupt control loops, reduce FEC effectiveness, and increase the BER. A rate equalizer function uses RAM buffering to convert stuttering data in the QAM Symbol Clock Domain to a uniform bit rate clock domain, without external components that would add to the implementation cost.

The programmable MCNS (Annex B) FEC circuit, which includes Trellis and Reed-Soloman decoders, has a 56-Kbit de-interleaver RAM. Outputs from the chip are an error-corrected serial bit stream and 8-bit soft decisions for each of the I and Q components of the QAM signal. An on-chip VCXO generates the 256Q and 64Q symbol rates, and an on-chip VCO produces the serial bit rates for 256Q and 64Q.

The HD49430F forms a complete and optimal solution for applications such as cable modems and set-top boxes with its companion HD49429F upstream processor.

HD49429F's High-Quality Analog Output Needs Only Simple Filtering

The HD49429F is a highly integrated, MCNS-compliant upstream processor that consists of a highly programmable encoder, Nyquist filter, and an RF modulator using a fully digital implementation. A very accurate on-chip 10-bit D/A converter (DAC) eliminates the need for an external DAC and produces a high-quality modulated analog RF carrier output that can be used after simple low-pass filtering. The 3.3-V chip also has an optimized, simplified interface to an external media access control (MAC) device; this facilitates external user implementations to MCNS or other standards. A general-purpose parallel port and serial I2C port allow external control.

The flexible, programmable architecture of the HD49429F's digital modulator can provide a modulated carrier from 1 to 42 MHz using a programmable numerically controlled oscillator (NCO) that has very high resolution. Multiple modulation types are supported: QPSK, 16 QAM, and p/4DQPSK symbol mapper. The 102.4 MHz internal synthesis clock is derived from an on-chip 5x multiplier to help reduce EMI and RF interference problems.

The programmable Nyquist filter on the HD49429F can implement a variety of signal standards (25% excess bandwidth, nominal), and the chip's programmable interpolators can produce a large number of related baud rates (from 160 Kbaud to 3.2 Mbaud) using a single crystal. Operation is burst mode or continuous (with no restrictions on continuous operation). The programmable bit stream formatting and encoding permits user control of RS (up to 20 parity bytes, 10 corrections), preamble (up to 1024 bits), and scrambling (with pseudo-bit random sequence per MCNS specifications).

Price and Availability

The Hitachi HD49430F downstream processor in a 100-pin plastic QFP is $13.95 in quantities of 50,000. The Hitachi HD49429F upstream processor in a 100-pin plastic QFP is $6.30 in quantities of 50,000. Samples of both devices are available now, and volume production will begin in the second quarter of 1998.

Two evaluation boards are available, one for the HD49430F and the other for the HD49429F. These boards can be separated for dedicated downstream or upstream communication, or combined for bi-directional communication. For more information, readers should contact their local Hitachi representative.

Reader Contact

Readers can request literature package PMDJQPR001P1 from Hitachi Semiconductor (America) Inc., 2000 Sierra Point Pkwy, MS-080, Brisbane, CA 94005-1897. Or they can call 1-800-285-1601 or Fax [phone] to request literature or for referral to the closest sales location.

They can also visit Hitachi's Web Site: http://www.hitachi.com/semiconductor

(Readers outside of North America should contact their local Hitachi representative.)

(a) Hitachi Enters Licensing Agreement with General Instrument Corporation Hitachi Semiconductor (America) Inc. has signed a patent license agreement with General Instrument Corporation (NYSE: GIC) under which Hitachi plans to incorporate several of General Instrument's patented cable modem technologies in the HD49430F downstream as well as other upcoming MCNS-compliant products.

About the MCNS Standard

The MCNS standard, developed by a consortium of North American cable operators, provides a common platform by which Internet Protocol (IP)-based data packets can travel over cable networks. Using this standard for IP data transmission over cable, MCNS allows developers of cable modems and related enabling technologies to concentrate engineering resources on increasing product differentiation and shortening the time-to-market.

About Hitachi

Hitachi Semiconductor (America) Inc., a subsidiary of Hitachi America, Ltd., supports the requirements of the North American marketplace with a broad range of standard and low power semiconductor solutions, including communication devices, Flash cards, Flash memories, Ferroelectric RAM devices, EEPROMs, MROMs, DRAMs, SDRAMs, DRAM modules, SGRAMs, SRAMs, ASICs, RISC and CISC microprocessors and embedded processors, LCD drivers/controllers, optoelectronic devices, cable/data modem ICs, hard disk drive ICs, and wireless communications components. Substantial design engineering, manufacturing, and research and development facilities in the United States help bring the world's best technology to U.S. customers.

Hitachi America, Ltd., a wholly owned subsidiary of Hitachi, Ltd., Japan, markets and manufactures a broad range of electronics, computer systems and products, semiconductors and provides industrial equipment and services throughout North America.

Hitachi, Ltd. (NYSE:HIT), headquartered in Tokyo, Japan, is one of the world's leading electronics companies, with fiscal 1996 consolidated sales (ending March 31, 1997) of $68.7 billion. The company markets and manufactures a wide range of products, including computers, semiconductors, consumer products and power and industrial equipment.

CONTACT: Hitachi Semiconductor (READER CONTACT)

Hitachi Semiconductor (America) Inc., 1-800/285-1601

Request literature package: PMDJQPR001P1

http://www.hitachi.com/semiconductor

(Readers outside of North America should contact their

local Hitachi representative.)

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