DMD15/DMD15L IBS/IDR Satellite Modem

Operation

 

 

3.10.2 Demodulator

The demodulator performs a complete digital implementation of a Variable-Rate Phase-Lock Satellite Receiver utilizing state-of-the-art digital signal processing techniques. The demodulator is capable of receiving nearly any modulation format. Signals enter the demodulator, are converted to baseband, split into ‘I’ In-Phase and ‘Q’ Quadrature Channels and digitized. The digitized I and Q Channels are then applied to a decimating FIR Matched Filter. After filtering, the signal is demodulated using a Costas Loop for recovery of the carrier and a clock recovery loop for recovery of bit timing. The demodulated data is then fed to a 1650 Viterbi Decoder, or Sequential Decoder if the option is installed. After decoding, the data is differentially decoded and descrambled.

3.11 DMD15/DMD15L Clocking Options

The following paragraphs define the types of clocking options available to the user at the Front Panel of the DMD15/DMD15L:

3.11.1 SCTE: Serial Clock Transmit External

This clock is the Transmit Terrestrial Clock associated with the interface. With the G.703 Interface selected, SCTE is the clock that is recovered from the G.703 data stream. SCTE is sometimes referred to as Tx Terrestrial Timing and for Synchronous Interfaces such as RS-422, SCTE is sometimes referred to as TT (Terminal Timing).

3.11.2 SCT: Serial Clock Transmit

This clock is an internally generated clock that is output from the modem. The clock is generally used by the Terrestrial Terminal equipment for clocking the transmit data. The frequency of the clock is set the same as the Transmit Terrestrial Clock rate if internal is selected, or is the receive clock from the Demodulator if SCR is selected. SCT is sometimes referred to as Internal Timing or ST (Send Timing).

3.11.4 EXT EXC: External Clock

This is an independent clock source. This clock is most often used if there is a station master clock. The EXT EXC can be selected, in the Interface/General Menu, to be balanced, bnc exc, sys rcs10, or IDI. IDI is used ONLY for D&I cases where external framing is selected. In this case the EXT EXC must be set to IDI where the Receive Buffer Clock is derived from the external Receive T1 or E1 Trunk.

3.11.5 BNC EXC: BNC External Clock

Unbalanced external clock input into BNC Connector J5.

Clock specification:

 

Frequency:

1 MHz – 10 MHz in 40 kHz steps

Level:

0.5 Vp-p – 5 Vp-p

3.11.6 BAL EXC: Balanced External Clock

This clock is input into J8-15-33, J7-7-8, or J18-13-47; all connectors are wired together for this clock and so only one connector pair should be driven at one time. The clock must meet RS-422 levels.

TM051 - Rev. 5.8

3-11

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Paradyne Demodulator, 11 DMD15/DMD15L Clocking Options, Scte Serial Clock Transmit External, SCT Serial Clock Transmit
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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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