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MTC20454

Power Supply Rejection

The noise on the power supplies for the RX-path must be lower than 50 mVrms in-band white noise for any

AVDD.

The pre-driver drives an external line power amplifier which transmits the required power to the line.

TX Filter

The TX filters act not only to suppress the DMT sidebands but also as smoothing filters on the D/A con-

verter’s output to suppress the image spectrum. For this reason they are realised in a time continuous ap-

proach.

ATU-C-TX Filter

Same filter as ATU-R-RX. Its purpose is now is to remove image frequency of the transmitted signal ac-

cording the ANSI definition.

Linearity of TX

Linearity of the TX is defined by the IM3 product of two sinusoidal signals with frequencies f1 and f2 and

each with 0.25 Vpd amplitude (-6 dB FS) at the output of the pre-driver for the case of a total AGC = 0 dB.

Power Supply Rejection

The noise on the power supplies for the TX-path must be lower than the following:

Figure 6. Power Supply Rejection

dB

-70

-60

-50

-40

1k

10k 100k1M 10M

Hz

TX Pre-driver Capability