參數(shù)資料
型號： T7234
英文描述： Compliance with the New ETSI PSD Requirement
中文描述： 符合新的ETSI PSD的要求
文件頁數(shù)： 93/116頁
文件大?。?/td> 1056K
代理商： T7234
Data Sheet
January 1998
T7256 Single-Chip NT1 (SCNT1) Transceiver
Lucent Technologies Inc.
89
Questions and Answers
(continued)
S/T-Interface
(continued)
Q36:
I would like to integrate a T7256-based NT1 onto
both a T7250C-based 4-wire TE product and a
T7903-based 4-wire TE product in order to pro-
vide a U-interface on these products. I realize this
can be done by simply incorporating my external
NT1 design directly onto the TE board, but is
there a simpler approach in which I can avoid
having two sets of S/T transformers and associ-
ated line interface circuitry
A36:
Yes. First note Figures 34, 35, and 36, which
show example S/T line interface circuits for the
T7256, T7903, and T7250C, respectively. If no
external S/T-interface connection is required, the
T7256 can be directly connected to the T7903
and T7250C as shown in Figures 37 and 38. If
there is a requirement for connecting external
TEs, the circuits shown in Figures 39 and 40 can
be used. These two circuits show a hybrid
scheme in which a direct connect between the
T7256 and T7903/T7250C is implemented while
providing for an external S/T-interface (thus
requiring only one set of S/T transformers rather
than the two sets that would be required if the
T7256 and T7903/T7250C were transformer-cou-
pled to one another instead directly connected).
The direct connect circuits were derived as
shown in Figures 37 and 38 and the following text
sections:
Note:
In all of these analyses, the final value of
resistance chosen may be slightly differ-
ent than the ideal value computed
because standard resistance values
were used.
T7903/T7250C Transmit to T7256 Receive
a) Transmitter Load:
T7903: The line interface transformer has a
turns ratio of 2.0, and the transmitter drives a
total line-side load of 50
. Reflecting this
impedance to the device side of the trans-
former results in 200
(50
x N
2
). This
resistance, combined with the 40
total
resistance of the device-side resistors,
results in a total of 240
that the transmitter
typically drives.
So, to optimize the transmitter part of the cir-
cuit based on the load the transmitter expects
to drive, the transmitter should see a total
resistance of approximately 240
.
T7250C: The line interface transformer has a
turns ratio of 2.5, and the transmitter drives a
line-side load of 50
. Reflecting this imped-
ance to the device side of the transformer
results in 312.5
(50
x N
2
). This resis-
tance, combined with the 113
total resis-
tance of the device-side resistors, results in a
total of 425.5
that the transmitter typically
drives. So, to optimize the transmitter part of
the circuit based on the load the transmitter
expects to drive, the transmitter should see a
total resistance of approximately 425
.
相關PDF資料
PDF描述
T7234A Compliance with the New ETSI PSD Requirement
T7237A Compliance with the New ETSI PSD Requirement
T7256A Compliance with the New ETSI PSD Requirement
T7288 CEPT/E1 Line Interface(CEPT/E1 線接口)
T7290A DS1/T1/CEPT/E1 Line Interface(DS1/T1/CEPT/E1 線接口)
相關代理商/技術參數(shù)
參數(shù)描述
T7234A 制造商:AGERE 制造商全稱:AGERE 功能描述:Compliance with the New ETSI PSD Requirement
T7237 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Compliance with the New ETSI PSD Requirement
T7237A 制造商:AGERE 制造商全稱:AGERE 功能描述:Compliance with the New ETSI PSD Requirement
T7240 制造商:TE Connectivity 功能描述:
T7-241A5 功能描述:撥動開關 ON NONE OFF 2 Pole Standard Bat Handle RoHS:否 制造商:OTTO 觸點形式: 開關功能: 電流額定值: 電壓額定值 AC: 電壓額定值 DC: 功率額定值: 端接類型: 安裝風格: 端子密封: 觸點電鍍: 照明:
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