Operation

DMD15/DMD15L IBS/IDR Satellite Modem

 

 

3.11.7 IDI: Insert Data In

This clock source is only used as an external frame source selected in D&I Mode. If External Frame Source is selected, then IDI must be selected for the buffer clock. For this case, a Receive T1/E1 Trunk is input into J5 and a buffer clock is derived.

3.11.8 SCR: Serial Clock Receive

This Receive Clock is recovered from the satellite’s receive signal from the satellite. SCR is sometimes referred to as Receive Clock, Satellite Clock, or as RT (Receive Timing).

3.11.9 EXT IF REF: External IF Reference

This is not actually a clock, but does have some clocking implications. When the external reference is used, the master oscillator within the DMD15/DMD15L is locked to the external reference, and the internal accuracy and stability of the DMD15/DMD15L assumes that of the External Reference. Therefore, not only are the transmit and receive frequencies of the DMD15/DMD15L locked to the external reference, but the modem’s internal SCT Oscillator is locked to the external reference as well.

3.12 Transmit Timing

As shown in Figure 3-7, Transmit Terrestrial Data enters the modem and is clocked into a Dejitter FIFO. Data is clocked out of the FIFO by the Modulator Clock. The Modulator Clock and Phase- Locked Loop (PLL), in conjunction with the Dejitter FIFO, reduces the input jitter. Jitter reduction exceeds the jitter transfer specified in CCITT G.821.

3.12.1 EXT CLK as TX Clock Source (RS-422 or V.35 Interface)

Data must be clocked into the modem by either the SCTE or SCT Source. If EXT CLK is selected as the Tx Clock Source, then SCTE must be supplied to the modem. The output of the dejitter buffer will be clocked with EXT CLK. This case should only be used if SCTE has excessive jitter and will degrade link performance.

3.12.2 SCT or SCTE

If SCT is selected, then only data that is synchronous to the SCT Clock is required to be supplied to the modem. It is intended for the terminal equipment to use the SCT as its clock source. The Autophase Circuit will automatically ensure that the data is clocked correctly into the modem.

Therefore, a return clock is not necessary. The Clock Polarity should be set to AUTO.

If SCTE is selected, then SCTE must be supplied to the modem. The Clock Polarity should be set to AUTO.

3.12.3 G.703 Interface

If the G.703 Interface is selected, then the Tx Clock Source must be set to SCTE and the Clock Polarity should be set to AUTO.

3.13 Receive Timing

Any of the clocking selections, SCTE, SCT, EXT CLK, or RxSat (SCR) may be selected as the Buffer Clock. Data will be clocked out of the buffer at the data rate synchronous to the selected clock source.

3-12

TM051 – Rev. 5.8

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Paradyne DMD15 IDI Insert Data, SCR Serial Clock Receive, EXT if REF External if Reference, Transmit Timing, SCT or Scte
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DMD15, DMD15L specifications

The Paradyne DMD15L and DMD15 are advanced digital modems designed to enhance communication in a variety of networking environments. As part of Paradyne's robust portfolio of networking solutions, these devices are engineered to deliver reliable and efficient data transmission over both copper and fiber optic connections.

One of the main features of the DMD15L and DMD15 is their capability to support Multiple Protocol Data Units (MPDUs), which enables them to handle a diverse range of network protocols seamlessly. This flexibility makes them suitable for different applications, from industrial automation to telecommunications.

These modems utilize advanced modulation techniques, such as Quadrature Amplitude Modulation (QAM), to maximize data throughput while maintaining signal integrity. This ensures that users benefit from high-speed connections, even in challenging signal environments. Furthermore, the DMD15 series incorporates Error Correction Codes (ECC) that enhance data reliability, effectively reducing packet loss and ensuring data coherence during transmission.

The DMD15L is particularly notable for its long-range capabilities, making it a go-to solution for users requiring extended distances without compromising data quality. It features built-in Adaptive Equalization, which automatically adjusts signal levels to optimize performance over varying transmission distances. This technology is crucial in maintaining consistent high-speed connectivity, especially in environments with variable conditions.

Both models are equipped with user-friendly interfaces that facilitate configuration and management. They support SNMP (Simple Network Management Protocol) for real-time network monitoring, allowing administrators to track performance metrics and identify potential issues before they impact users. The devices also include LED indicators for quick status checks, ensuring that users have immediate visibility of operational conditions.

In terms of physical characteristics, the DMD15 and DMD15L are designed for durability and ease of installation. They come in a compact form factor, making them suitable for deployment in constrained spaces. Additionally, their robust casing is built to withstand harsh environmental conditions, making them suitable for both indoor and outdoor installations.

Overall, the Paradyne DMD15L and DMD15 are high-performance modems that combine versatile technologies, reliability, and user-friendly features. They are excellent choices for organizations looking to enhance their communication capabilities and ensure robust data transmission across diverse networks. With their advanced functionalities and adaptability, these modems stand out as key components in modern network infrastructure.
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