MT9076BB1 Просмотр технического описания (PDF) - Zarlink Semiconductor Inc

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Компоненты Описание

производитель

MT9076BB1

T1/E1/J1 3.3 V Single Chip Transceiver

Zarlink Semiconductor Inc 

Peak to Peak

Jitter Amplitude

(log scale)

18UI

MT9076B

MT9076

Tolerance

Data Sheet

1.5UI

0.2UI

1.667 Hz 20 Hz

Jitter Frequency

(log scale)

2.4 kHz 18 kHz 100 kHz

Figure 4 - Input Jitter Tolerance as Recommended by G.823 and ETSI 300 011 (E1)

1.2 Transmitter

The transmit portion of the MT9076 LIU consists of a high speed digital-to-analog converter and complementary

line drivers.

When a pulse is to be transmitted, a sequence of digital values (dependent on transmit equalization) are read out of

a ROM by a high speed clock. These values drive the digital-to-analog converter to produce an analog signal,

which is passed to the complementary line drivers.

The complementary line drivers are designed to drive a 1:2.4 step-up transformer in T1 mode and either a 1:2 or

1:2.4 step-up transformer in E1 mode (see Figure 5). A 0.47 uF capacitor is required between the TTIP and the

transmit transformer. Resistors RT (as shown in Figure 5) are for termination for transmit return loss. The values of

RT may be optimized for T1 mode, E1 120 Ω lines, E1 75 Ω lines or set at a compromise value to serve multiple

applications. Program the Tx LIU Control Word (page 02H, address 11H) to adjust the pulse amplitude accordingly.

Alternatively, the pulse level and shape may be discretely programmed by writing to the Custom Pulse Level

registers (page 2, addresses 1CH to 1FH) and setting the Custom Transmit Pulse bit high (bit 3 of the Tx LIU

Control Word). In this case the output of each of the registers directly drives the D/A converter going to the line

driver. Table 1 and Table 2 show recommended transmit pulse amplitude settings.

In T1 mode, the template for the transmitted pulse (the DSX-1 template) is shown in Figure 6. The nominal peak

voltage of a mark is 3 volts. The ratio of the amplitude of the transmit pulses generated by TTIP and TRING lie

between 0.95 and 1.05.

In E1 mode, the template for the transmitted pulse, as specified in G.703, is shown in Figure 7. The nominal peak

voltage of a mark is 3 volts for 120 Ω twisted pair applications and 2.37 volts for 75 Ω coax applications. The ratio of

the amplitude of the transmit pulses generated by TTIP and TRING lie between 0.95 and 1.05.

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Zarlink Semiconductor Inc.

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