Demodulator provides reliable reception for China viewers

With the rapid growth of digital TV market in China, Micronas GmbH has launched the DRX 398yZ family of digital terrestrial demodulators. This demodulates high-definition and standard-definition television signals that meet China's GB20600-2006 requirements, which is popularly known as digital TV multimedia broadcast (DTMB). The chip is widely integrated and fits various applications such as STBs, personal video recorders, integrated digital TVs, network interface modules, USB-TV sticks and PC-TV cards. In August 2006, China released its own digital TV terrestrial broadcast transmission standard, GB20600-2006, which includes both single-carrier and multicarrier modulations.

The DTMB demodulator works automatically in detecting single-carrier and multicarrier modes. It offers excellent reception performance for both modes. In a single-carrier system, this is used via the integrated time-domain equalizer that provides an adaptive decision-feedback algorithm. Meanwhile, a multicarrier system is made via the frequency domain equalizer with the help of advanced channel estimator.

Going extra mile
"DTMB is one of the most complex broadcast transmission standards," said Zhenning Zhang, marketing manager, Micronas Shanghai. "Our experience in developing advanced demodulator systems for Advanced Television Systems Committee and Digital Video Broadcasting allowed us to create a device that surpasses all DTMB requirements enabling a robust and reliable reception performance," he added.

The demodulator provides a higher integration level that allows TV makers to reduce cost in purchasing parts and to make the designs simpler. The device is requiring only one 8MHz SAW filter, and includes pulse-width modulator RF-AGC and IF-AGC outputs. It includes a high-speed 10bit ADC, a high-quality PLL that permits the use of a simple crystal as clock reference and SDRAM for de-interleaving.

Multiple versions
The DRX 398yZ offers exceptional digital reception performance. It provides robust synchronization in the presence of phase and frequency offsets up to 500kHz and higher timing recovery up to 100ppm of sampling offset. An on-chip microprocessor performs autonomous detection and operation of all possible DTMB modes without stressing the host processor.

Customers are given a wide selection among the three versions of the device to meet their specific design requirements. There are single-carrier version, multicarrier version and the one that supports both modes. All versions come in a QFN64 package and are pin-and-driver compatible with the other products in the DRX-series.

There are also a range of software modules to control the device, including integrated tuner support. All modules have a common API. This approach enables accelerated design times for quick time-to-market, which is essential in today's competitive environment.