PEF2091 Siemens Semiconductor Group, PEF2091 Datasheet - Page 259

• Manufacturer Part Number: PEF2091
• Description: ICs for Communications(ISDN Echocancellation Circuit)
• Manufacturer: Siemens Semiconductor Group

7.4
With a number of operational modes the IEC-Q supports system measurements. These
modes along with the most frequently needed system measurements are described in
the following sections.
7.4.1
The SSP-test mode is required for pulse mask measurements.
In this test mode, the IEC-Q transmits on the U-interface alternating
by 1.5 ms. This test mode is used in LT and NT like modes. Three options exist for
selecting the “Send-Single-Pulses" (SSP) mode:
– hardware selection:
– software selection:
– microprocessor selection
All methods are fully equivalent. In the SSP mode the C/I-code transmitted by the IEC-Q
is DEAC in LT modes and DR in the NT modes.
Pulse Mask Measurement
– Pulse mask is defined in ANSI T1.601 and ETSI TS 101080
– U-interface has to be terminated with 135
– IEC-Q is in “Single-Pulses" mode
– Measurements are done using an oscilloscope
7.4.2
The DT mode is required for power spectral density and total power measurements.
When selecting the data-through mode, the IEC-Q is forced directly into the
“Transparent" state. This is possible from any state in the state diagram.
The Data-Through option (DT) provides the possibility to transmit a standard scrambled
U-signal even if no U-interface wake-up protocol is possible. This feature is of interest
when no counter station can be connected to supply the wake-up protocol signals. The
DT-test mode may be used in LT and NT like applications.
As with the SSP mode, three options are available.
– hardware selection:
– software selection:
– microprocessor selection
Semiconductor Group
Set-ups for Test Modes and System Measurements
Tests in Send Single Pulses Mode
Tests in Data-Through Mode
C/I = SSP (0101
C/I = DT (0110
RESQ = 1 & TSP = 1
Bits (STCR:TM1 = 1) and (STCR:TM2 = 1)
RESQ = 0 & TSP = 1
Bits (STCR:TM1 = 0) and (STCR:TM2 = 1)
259
B
)
B
)
Application Hints
3 pulses spaced
Data Sheet 01.99
PEB 2091
PEF 2091