XRT83VSH28IB datasheet(32/74 Pages) EXAR

32 / 74 page

XRT83VSH28

PRELIMINARY

8-CHANNEL E1 SHORT-HAUL LINE INTERFACE UNIT

REV. P1.0.0

3.3

Transmit Jitter Attenuator

The XRT83VSH28 LIU is ideal for multiplexer or mapper applications where the network data crosses multiple

timing domains. As the higher data rates are de-multiplexed down to E1 data, stuffing bits are typically

removed which can leave gaps in the incoming data stream. The transmit path has a dedicated jitter attenuator

with a 32-Bit or 64-Bit FIFO that is used to smooth the gapped clock into a steady E1 output. The maximum

gap width of the 8-channel LIU is shown in Table 7.

NOTE: If the LIU is used in a loop timing system, the receive path has a dedicated jitter attenuator. See the Receive

Section of this datasheet.

3.4

TAOS (Transmit All Ones)

The XRT83VSH28 has the ability to transmit all ones on a per channel basis by programming the appropriate

channel register. This function takes priority over the digital data present on the TPOS/TNEG inputs. For

example: If a fixed "0011" pattern is present on TPOS in single rail mode and TAOS is enabled, the transmitter

will output all ones. In addition, if digital or dual loopback is selected, the data on the RPOS output will be

equal to the data on the TPOS input. Figure 16 is a diagram showing the all ones signal at TTIP and TRING.

FIGURE 16. TAOS (TRANSMIT ALL ONES)

3.5

Transmit Diagnostic Features

In addition to TAOS, the XRT83VSH28 offers diagnostic features for analyzing network integrity such as

ATAOS and QRSS on a per channel basis by programming the appropriate registers.

These diagnostic

features take priority over the digital data present on TPOS/TNEG inputs. The transmitters will send the

diagnostic code to the line and will be maintained in the digital loopback if selected.

When the LIU is

responsible for sending diagnostic patterns, the LIU is automatically placed in the single rail mode.

3.5.1

ATAOS (Automatic Transmit All Ones)

If ATAOS is selected by programming the appropriate global register, an AMI all ones signal will be transmitted

for each channel that experiences an RLOS condition. If RLOS does not occur, the ATAOS will remain inactive

until an RLOS on a given channel occurs. A simplified block diagram of the ATAOS function is shown in

Figure 17.

TABLE 7: MAXIMUM GAP WIDTH FOR MULTIPLEXER/MAPPER APPLICATIONS

FIFO DEPTH

MAXIMUM GAP WIDTH

32-Bit

20 UI

64-Bit

50 UI

TAOS

111

XRT83VSH28IB датащи(PDF) 32 Page - Exar Corporation

XRT83VSH28IB датащи(HTML) 32 Page - Exar Corporation

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74

датащи скачать

ссылки URL