DOCSIS 3.1 test setups aided by signal generator

20th April 2015

Mick Elliott

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Transmitting high-definition 4K UHD contents to consumers' households requires large bandwidths. Capacity requirements for IP based services are also on the rise. Enter new broadband technologies such as DOCSIS 3.1. The new DOCSIS 3.1 standard enables data rates of several Gbit/s for IP-based transmissions in cable networks. Rohde & Schwarz is offering the R&S CLGD signal generator for network component development and receiver tests.

The generator can simulate channel loading scenarios composed of DOCSIS 3.1, digital (J.83/A/B/C) and analogue TV signals in the downstream, and DOCSIS 3.1 along with DOCSIS 3.0 signals in the upstream.

Typical applications for the signal generator include broadband tuner development for the new generation of cable modems and comprehensive receiver tests. It is also well suited for qualification tests on amplifiers and electrical/optical converters with DOCSIS 3.1 signals.

With a frequency range of 47 MHz to 1218 MHz (optionally up to 1794 MHz) for the downstream, the R&S CLGD can simultaneously generate up to six 192 MHz DOCSIS 3.1 channels or up to 160 QAM channels.

It is also possible to use a combination of both channel types. Each individual channel is continuously modulated in real time, enabling bit error rate (BER) measurements on each channel across the entire frequency range without requiring any changes to existing configurations.

To create real-world conditions, the signal generator also simulates different types of interference such as additive white Gaussian noise (AWGN), impulsive noise, microreflections (in line with SCTE 40), narrowband ingress and 50 Hz/60 Hz AC hum.

The R&S FSW-K192 option for the R&S FSW signal and spectrum analyser makes it possible to analyse DOCSIS 3.1 OFDM downstream signals.

The software offers features that simplify precise DUT characterisation and troubleshooting and carry out signal analysis fast and reliably. Typical DOCSIS 3.1 signal parameters are detected automatically, allowing users without detailed knowledge of the standard to carry out all measurements at the press of a button.

Due to its wide dynamic range, the R&S FSW signal and spectrum analyser with the R&S FSW-K192 option can measure the key parameters determining signal quality with great accuracy.

With a residual modulation error ratio (MER) of 57 dB, the R&S FSW8 sets the current industry standard.

A wide choice of graphical displays is available for visualising measurement results; for example, the MER value across all OFDM carriers of a DOCSIS 3.1 signal can be shown.