AOpen XRecorder VX2000 - Page 2

- Internal parts

The CS92288 real-time audio/video codec is the heart of the XRecorder. This versatile chip from Cirus Logic supports both the MPEG-1 and MPEG-2 digital video standards, as well as the Dolby Digital and MPEG digital audio standards. It enables high quality video and audio playback across a wide range of bit rates.

The photo below shows the inside of the XRecorder with the Philips TV tuner prominent. The tuner provides very good TV reception. However, all the high tech stuff is on the daughterboard to the right of the tuner, where there are a number of very interesting chips being used. Among them the TSB41AB2 IEEE 1394a-2000 two-port cable transceiver/arbiter from Texas Instruments, the HY57V643220C CMOS Synchronous DRAM from Hynix, the PDI11394L40 full duplex 1394 A/V LLC from Philips and the NW721 DV Codec from Divio.

• The Hynix HY57V643220C is a 67,108,864-bit CMOS Synchronous DRAM, ideally suited for memory applications which require wide data I/O and high bandwidth. The HY57V643220C is organized as 4 banks of 512k x 32bits.

• The PDI11394L40 from Philips Semiconductor, a full duplex 1394 Audio/Video (AV) Link Layer Controller, is an IEEE 1394a-2000 compliant link layer controller featuring 2 embedded AV layer interfaces. The application data is packetized according to the IEC 61883 International Standard of Interface for Consumer Electronic Audio/Video Equipment. Both AV layer interfaces are byte-wide ports capable of accommodating various MPEG-2 and DVC codecs. A flexible host interface is provided for internal register configuration as well as performing asynchronous data transfers. Both 8 bit and 16 bit wide data paths, as well as multiplexed/non-multiplexed access modes are supported.

• Texas Instruments TSB41AB2 provides the digital and analog transceiver functions needed to implement a two-port node in a cable-based IEEE 1394 network. The cable ports incorporate two differential line transceivers. The transceivers include circuitry to monitor the line conditions as needed for determining connection status, for initialization and arbitration, and for packet reception and transmission.

• The NW721 from Divio provides a bi-directional digital-to-digital path to next generation digital storage, display and editing devices including DVD recorders, Digital TVs, flat screen displays, projectors, set top boxes, PCs and MACs. The NW721 DV Codec provides full video Codec functionality between IEC-61834 (DV) and ITU-R BT656. It ensures pure digital A/V processing including complete audio and AUX code processing. The NW721 full Codec functionality adds real-time output and editing capabilities to industry-standard decoding, for both NTSC (30 fps) and PAL (25 fps) systems.

Underneath the daughterboard, on the main board is the Cirus Logic CS92288 shown below (all that can be seen here is the fan unit. We made no attempts to disect the unit any further).

A problem here was the large amount of noise the unit produced. After opening the box and peeking inside, we discovered the culprit was the fan attached to the heat sink of the Cirrus Logic hardware MPEG2 chip. The noise levels that it produced were rather annoying, even after a small “fix” we applied in an effort to stop it from making noise. We trust that the problem was in the sample we got for our testing purposes.