PEF22827EL-V11 Lantiq, PEF22827EL-V11 Datasheet - Page 62

• Manufacturer Part Number: PEF22827EL-V11
• Manufacturer: Lantiq

Specifications of PEF22827EL-V11

• Lead Free Status / RoHS Status: Supplier Unconfirmed

4.3.2
The QAM demodulator receives a sampled signal from the ADC in the analog block,
demodulates the QAM symbols from the two modulated carriers and delivers the two bit
streams to the TC layer.
The incoming signal from the analog block is delivered over a 12-bit bus at the rate of
the 38.88 MHz system clock for 4-band standard-compliant applications. The incoming
signal contains the two modulated received carriers.
The received modulated signal is split into two signals and the following processes are
performed on both streams, in the order shown:
1. Digital AGC processing
2. Downward frequency conversion
3. Filtering
4. Decimation
5. Equalization
6. Symbol to bit mapping. Supported constellations are QAM-2 through QAM4096.
Demodulation also includes a timing recovery mechanism and an analog AGC control
unit. The timing recovery mechanism in NT modems tracks timing and carrier
frequencies. In VDSL, a single tracking mechanism tracks both timing and carrier
frequency, which are both derived from the system clock.
The timing recovery mechanism in the digital transceiver tunes the system clock by
programming the tuning register in the analog block through a serial control interface.
The digital transceiver also programs the analog AGC in the analog block through the
serial control interface.
To configure PMD layer parameters, see
4.4
PMS-TC layer is located between the Physical Media Dependent (PMD) and the
Transport Protocol Specific Transmission Convergence (TPS-TC) layers. The PMS-TC
layer supports transfer of slow and fast data channels, overhead channels and link
control information.
To configure PMS-TC layer parameters for standard 4-band firmware, see
Target STPs” on Page
4.4.1
In the transmission path, the PMS-TC layer does the following:
•
•
Preliminary Data Sheet
Scrambling
Reed Solomon Encoding
QAM Demodulator (Receiver)
Physical Medium Specific Transmission Convergence (PMS-TC)
Layer
Transmission Path Tasks
104.
“Current and Target STPs” on Page
62
Functional Description – Digital Block
Rev. 1.1, 2005-01-30
“Current and
VDSL6100i
PEF 22827
104.