PEB24901HV12 Lantiq, PEB24901HV12 Datasheet - Page 24

• Manufacturer Part Number: PEB24901HV12
• Manufacturer: Lantiq

Specifications of PEB24901HV12

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PEB 24901
coefficients. This filter emulates the line characteristics in order to cancel the echoed
data from the received signal and to regain the data from the far end. Because these
coefficients characterize the line, being a time discrete pulse response, it is of great
interest to read them out of the IEC and evaluate them to localize possible faults in the
two wire loop.
The 16 most significant bits of the echocanceller coefficients can be read out via the
MONITOR-channel. To reduce internal circuitry, these coefficients have a rather
complicated format.
Figure 8
Transposition of EC Coefficient to MONITOR-Channel
The low byte of a coefficient is to be accessed with an even numbered address in the
MONITOR-channel, the high byte with an odd numbered address. The coefficient to
cancel the first echo is therefore accessible under addresses 04 H and 05 H ; the last
coefficient is found in addresses 62 H and 63 H . Both bytes are requested via the Monitor
command addressing the high byte of one coefficient. For instance if the second
coefficient is requested with the Monitor command "80 06", the Quad IEC DFE-T will
answer with a four byte message giving the high byte (adress 06) and the the low byte
(adress 07): 88 06 "data byte" 8C 07 "data byte".
To avoid a carry from low to high, caused by continuous adaption between the readouts
of the low and the high byte, the coefficients are stored after a monitor command
"Coefficients" and read out
while the echocanceller allready may compute new
coefficients.
3.2.1.2.3 Setting the Driver Pins
Each channels owns four data pins Dij, where i = 0, 1, 2, 3 denotes the channel and j =
A, B, C, D specifies the pin. They are set with a two-byte Monitor command 81 7x
,
H
where x is the hexadecimal notation of the binary value of the pins: x
= D C B A
.
H
bin
The setting of the driver pins is not affected by a C/I reset.
Semiconductor Group
23
02.95