DMA2286 datasheet(4/48 Pages) MICRONAS

4 / 48 page

DMA 2275, DMA 2286

The DMA 2275 and DMA 2286 C/D/D2–MAC De-

scrambler

1. Introduction

1.1. General Information

The DMA 2275 is a digital real–time descrambling pro-

cessor for the D2–MAC/Packet system. Together with

the D2–MAC/Packet decoder chip DMA 2271, it can be

used to build up a D2–MAC/Packet conditional access

receiver.

The DMA 2286 is a digital real–time descrambling pro-

cessor for the C/D/D2–MAC/Packet system. Together

with the C/D/D2–MAC/Packet decoder chip DMA 2281,

it can be used to build up a C/D/D2–MAC/Packet condi-

tional access receiver.

The programmable VLSI circuits in CMOS technology

are housed in 68–pin packages and contain on a single

silicon chip the following functions:

DMA 2275 and DMA 2286

– descrambling of MAC video signal

– interpolation of MAC video signal (aspect ratio 16:9)

– descrambling of MAC data packets

– descrambling of VBI–teletext

– entitlement packet acquisition

– supplementary general purpose packet acquisition

– line 625 acquisition

– communication with external microprocessor via the

IM bus

DMA 2286 only

– one subframe sound processing C/D/D2–MAC

1.2. Environment

Figures 1–1 and 1–2 show how the descrambler chips

DMA 2275 and DMA 2286 can be implemented into a

MAC conditional access receiver together with other cir-

cuits of ITT’s DIGIT 2000 digital TV system. These re-

ceivers provide descrambling facility for one video ser-

vice and up to four audio or data services including

VBI–teletext. It is important to notice that the DMA 2275

or DMA 2286 do not include any decryption or security

functions. These functions will be carried out by one or

more conditional access subsystems (CASS) which

communicate with the descrambler chip via the central

control unit (CCU) and the IM bus.

D2MAC

Baseband

Signal

CASS

VCU 2133

A/D Part

MCU 2600

NVM 3060

DRAM

DMA 2271

VCU 2133

D/A Part

AMU 2481

Fig. 1–1: Block diagram for a stand–alone D2–MAC

decoder

TPU 2735

DRAM

DMA 2275

DRAM

CCU 3000

CASS

VCU 2133

A/D Part

MCU 2600

NVM 3060

DRAM

DMA 2281

VCU 2133

D/A Part

AMU 2481

TPU 2740

DRAM

DMA 2286

DRAM

CCU 3000

D/D2MAC

Baseband

Signal

DRAM

Fig. 1–2: Block diagram for a stand–alone D/D2–

MAC decoder

DMA2286 Datasheet(PDF) 4 Page - Micronas

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