01 block diagram
DESCRIPTION
05 Tt2550eu01alTRANSCRIPT
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_011
Contents
1 Transmit Side 3
2 Receive Side 7
3 Exercise 11
Block Diagram of a Primary Multiplexer
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_012
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_013
1 Transmit Side
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_014
The required functional entities of the DSMX 64 K/2F are accordingly subdivided intoa transmit section and a receive section. The transmit section incorporates thetransmit unit and transmit-side speech circuits in the telephone channel units or thetransmit-side circuits of the data channel units; the receive section comprises thereceive unit and the receive-side speech circuits in the telephone channel units or thereceive-side circuits of the data channel units.
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_015
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VF
A
D
VFA
D
~~~
~~~
A/D = Analog-Digital converter
Dec = Decoder
SMX = Signaling multiplexer
PCM
Combining
2 Mbit/s
signal
Supervision
Gen. of frame
alignment
signalbits
D, N,
Y
Clock
generation
Alarm
output
DS30
Dec
SMX
F1 out.
.
.
Fig. 1 Block diagram of transmit side, showing functional blocks
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_016
Telephone Channel Unit
The transmit-side speech circuit takes over the telephone signals present on theassociated telephone lines (VF signals). The signals are band-limited from 300 Hz to3400 Hz.
Depending on the required relative level setting, the signal is amplified or attenuatedbefore the A/D conversion. The relative level in transmit direction is referred to theinput of the A/D converter. Thus a relative level setting of -14 dBr means that thelevel before the amplifier is 14 dB less than at the input of the A/D converter. Withother terms the signal is amplified by 14 dB.
The resulting PAM values (pulse amplitude modulation) are converted into 8-bit codewords by the encoder. This non-linear quantizing is amplitude-dependent. Theencoding characteristic (A-law), which is symmetrical with respect to the zero line,consists of 13 linear segments, giving an approximately logarithmic response.
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_017
2 Receive Side
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_018
The 2 Mbit/s PCM-E signal is fed to all the channels and the signaling multiplexer.The addressing, which is derived from the clock generator, ensures that the individual8-bit words are read into the associated channel units or the signaling multiplexerwith the correct timing.
The functional blocks synchronization and sections of the clock generator anddistributor are concentrated in a highly integrated I2L device mounted in the transmitunit (PCM receive device).
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_019
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
VF
A
D
VFA
D
~~
~~
A/D = Analog-Digital converter
Dec = Decoder
SMX = Signaling multiplexer
PCM-E
Distribution and evaluation
2 Mbit/s
signal
Supervision
Det. of frame align. sig. andeval. of parity
bitbits
D, N,
Y
Clock
generation
Alarm
output
DS30
Cod
SMX
F1 in.
.
.
Fig. 2 Block diagram of the receive side
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_0110
Telephone Channel Unit
The PAM signal is generated from the 8-bit words in the decoder. A low-pass filterwith (sin x) / x equalization reconverts the sample-and-hold signal formed from thesequence of PAM values to the VF signal.
Depending on the required relative level setting the signal is amplified or attenuatedafter the D/A converter. The relative level in receive direction is referred to the outputof the D/A converter. Thus a relative level of 4 dBr means that the level after theamplifier is 4 dB higher than at the output of the D/A converter. With other terms thesignal is amplified by 4 dB.
Data Channel Unit
The 8-bit words are read into a memory with the 2-MHz receive clock, undergo serial-parallel conversion and are then read out again at 64 kHz. The 64 kbit/s signal is thenencoded and fed out from D2out at 256 kbaud.
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_0111
3 Exercise
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_0112
Block Diagram of a Primary Multiplexer Siemens
TT2550EU01AL_0113
Exercise
Which blocks of the primary multiplexer may be distinguished for the application ofvoice channel transmission and data channel transmission?
Siemens Block Diagram of a Primary Multiplexer
TT2550EU01AL_0114