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| 型号： | DS26503 |
| 英文描述： | T1/E1/J1 BITS Element |
| 中文描述： | T1/E1/J1 BITS单元 |
| 文件页数： | 78/123页 |
| 文件大小： | 995K |
| 代理商： | DS26503 |
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DS26503 T1/E1/J1 BITS Element
78 of 123
13.1 LIU Operation
The analog AMI/HDB3 waveform off of the E1 line or the AMI/B8ZS waveform off of the T1 line is
transformer-coupled into the RTIP and RRING pins of the DS26503. The user has the option to use
internal termination, software selectable for 75
/100
/110
/120
applications, or external termination.
The LIU recovers clock and data from the analog signal and passes it through the jitter attenuation mux.
The DS26503 contains an active filter that reconstructs the analog received signal for the nonlinear losses
that occur in transmission. The receive circuitry also is configurable for various monitor applications. The
device has a usable receive sensitivity of 0dB to -43dB for E1 and 0dB to -36dB for T1, which allows the
device to operate on 0.63mm (22AWG) cables up to 2.5km (E1) and 6000 feet (T1) in length. Data from
the framer portion of the part is sent via the jitter attenuation MUX to the wave shaping circuitry and line
driver. The DS26503 will drive the E1 or T1 line from the TTIP and TRING pins via a coupling
transformer. The line driver can handle both CEPT 30/ISDN-PRI lines for E1 and long-haul (CSU) or
short-haul (DSX-1) lines for T1.
13.2 LIU Receiver
The DS26503 contains a digital clock recovery system. The DS26503 couples to the receive line via a 1:1
transformer. The DS26503 has the option of using software-selectable termination requiring only a single,
fixed pair of termination resistors.
The DS26503’s LIU is designed to be fully software selectable for E1 and T1 without the need to change
any external resistors for the receive-side. The receiver will allow the user to configure the DS26503 for
75
, 100
, 110
, or 120
receive termination by setting the RT0(LIC4.0), RT1(LIC4.1), and
RT2(LIC4.2). When using the internal termination feature, the resistors labeled R in
Figure 13-4
should
be 60
each. If external termination is required, RT0, RT1, and RT2 should be set to zero and the
resistors labeled R in
Figure 13-4
will need to be 37.5
, 50
, 55
, or 60
each, depending on the line
impedance.
There are two ranges of receive sensitivity for both T1 and E1, which is selectable by the user. The EGL
bit of LIC1 (LIC1.4) selects the full or limited sensitivity.
The resultant E1 or T1 clock derived from MCLK is multiplied by 16 via an internal PLL and fed to the
clock recovery system. The clock recovery system uses the clock from the PLL circuit to form a 16 times
over-sampler, which is used to recover the clock and data. This over-sampling technique offers
outstanding performance to meet jitter tolerance specifications shown in
Figure 13-6
and
Figure 13-7
.
Normally, the clock that is output at the RCLK pin is the recovered clock from the waveform presented at
the RTIP and RRING inputs. If the jitter attenuator is placed in the receive path (as is the case in most
applications), the jitter attenuator restores the RCLK to an approximate 50% duty cycle. If the jitter
attenuator is either placed in the transmit path or is disabled, the RCLK output can exhibit slightly shorter
high cycles of the clock. This is due to the highly over-sampled digital clock recovery circuitry. See the
Receive AC Timing Characteristics
section for more details. When no signal is present at RTIP and
RRING, a receive loss of signal (RLOS) condition will occur and the RCLK will be derived from the
JACLK source.
13.2.1 Receive Level Indicator
The DS26503 will report the signal strength at RTIP and RRING in 2.5dB increments via RL3-RL0
located in the Information Register 1 (INFO1). This feature is helpful when trouble shooting line
performance problems.
相关PDF资料 |
PDF描述 |
|---|---|
| DS26503L | T1/E1/J1 BITS Element |
| DS26503LN | T1/E1/J1 BITS Element |
| DS26503 | T1/E1/J1/64KCC BITS Element |
| DS26LV3 | 16 AMP LOW PROFILE POWER RELAY |
| DS2703 | SHA-1 Battery Pack Authentication IC |
相关代理商/技术参数 |
参数描述 |
|---|---|
| DS26503_07 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:T1/E1/J1 BITS Element |
| DS26503DK | 功能描述:时钟和定时器开发工具 DS26503 Dev Kit RoHS:否 制造商:Texas Instruments 产品:Evaluation Modules 类型:Clock Conditioners 工具用于评估:LMK04100B 频率:122.8 MHz 工作电源电压:3.3 V |
| DS26503L | 功能描述:计时器和支持产品 E1-T1-J1 Bits Element RoHS:否 制造商:Micrel 类型:Standard 封装 / 箱体:SOT-23 内部定时器数量:1 电源电压-最大:18 V 电源电压-最小:2.7 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
| DS26503L+ | 功能描述:计时器和支持产品 E1-T1-J1 Bits Element RoHS:否 制造商:Micrel 类型:Standard 封装 / 箱体:SOT-23 内部定时器数量:1 电源电压-最大:18 V 电源电压-最小:2.7 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
| DS26503LN | 功能描述:计时器和支持产品 E1-T1-J1 Bits Element RoHS:否 制造商:Micrel 类型:Standard 封装 / 箱体:SOT-23 内部定时器数量:1 电源电压-最大:18 V 电源电压-最小:2.7 V 最大功率耗散: 最大工作温度:+ 85 C 最小工作温度:- 40 C 封装:Reel |
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