Single-IC tuner brings digital TV home
By Bill Schweber -- EDN, August 5, 2004
Targeting advanced satellite set-top boxes and high-definition TV, the Zarlink ZL10038 IC complies with the Digital Video Broadcast-Satellite 2 international standard, which the vendor says is the first such device to do so (Picture). This broadcast standard provides 30% more bandwidth than previous satellite standards, for 25 standard-definition or six high-definition channels through a 33-MHz transponder, and accommodates modulation modes such as 8-PSK (phase-shift keying), 16-QAM (quadrature-amplitude modulation), and 16/32 APSK (asymmetric PSK).
This L-band-to-zero-IF quadrature downconverter operates over the 950- to 2150-MHz band, supporting symbol rates of 1 million to 45 million symbols/sec. The tuner IC includes selectable RF-bypass, low-noise-amplifier, PLL-based synthesizer, and baseband filters; a VCO that needs no alignment or calibration; and a bidirectional serial-control interface. Its I/Q quadrature channels are balanced to better than ±3° and ±0.6 dB; phase jitter is less than 2°.
The 5V IC requires a reference crystal and offers a dynamic range of –92 to –10 dBm without an RF attenuator or RSSI (received-signal-strength-indicator) function. The vendor claims that an overall tuner design based on this $4.55 (1000) ZL10038 occupies less than 20×30 mm of board space.
Zarlink Semiconductor Inc, 1-613-592-0200, www.zarlink.com.
