RFM220 ISDB-Tb Measurement Demodulator

Features & Benefits

• Comprehensive ISDB-Tb RF measurement and monitoring capabilities including overall and separate MER per layer (one for HDTV, one for the 1-seg), TMCC information monitoring, and Channel Impulse Response display with SFN window measurements plus Constellation and Spectrum displays with shoulder measurements help to identify degradations in transmitter performance and efficiency before viewers are impacted
• High-performance tuner/demodulator with MER measurement performance to 36 dB typ. offers the flexibility needed for use in both transmitter monitoring and off-air ISDB-Tb broadcast applications
• Remote access to monitoring functionality with user-configurable alarm reporting, event logs, and 7-day trending enables remote notification and reporting to engineers and operators of transmission system problems
• Transport Stream output enables connection to MPEG TS monitoring systems, including Tektronix MTM400A or Sentry products, offering a flexible and affordable monitoring solution to quickly identify and isolate problems in either the Transport Stream or the RF signal

Applications

• RF performance monitoring of local and remote ISDB-Tb transmitter sites
• Off-air monitoring at local and national operation centers and headends

Introduction

The RFM220 is a measurement demodulator for broadcast network operators who deploy and maintain ISDB-Tb broadcast networks by providing remote monitoring of all key ISDB-Tb broadcast RF parameters, with 7-day long-term trending, high-performance diagnostic RF capabilities, and event logging for unattended operation. Product specification summary is shown below:

• RF Specs
• Frequency: 170-230 MHz / 470-862 MHz
• Bandwidth: 6 MHz
• Input Sensitivity: –30 dBm / –90 dBm
• Max Input Level: 0 dBm
• RF Measurements
• Input Level: –50 dBm to –30 dBm
• Resolution: 0.1 dB
• Accuracy: <2 dB typ.
• MER (with individual MER for both layers): 28 dB to 36 dB typ., Resolution 0.1 dB Accuracy ±1.5 dB
• SNR
• BER (post Viterbi / pre RS)
• PER (Uncorrected packet post RS)
• Carrier Frequency Offset (CFO)
• Left and Right Shoulder Attenuation
• Measurement Displays
• TMCC Data Display
• Channel Impulse Response (Delay Profile) with 5 main echoes in SFN window
• Constellation Display (merged and individual layer)
• Spectrum Display
• Other
• Remote Web Access and Control
• SNMP Traps for 3rd-party Management Systems
• Demodulated ASI Output
• ASI Input

Product Information

Combined RF and TS Monitoring.

The RFM220 product is a 1RU rackmount product that can be used as a stand-alone RF monitoring solution or used in conjunction with an MTM400A to provide combined RF and TS monitoring.

RF and ASI Inputs

RFM220 Measurement Demodulator with RF Monitoring Remote Interface.


MTM400A with RFM220 Measurement Demodulator and both RF and TS Remote User Interfaces.


MTM400A with DVB-S2 Measurement Interface and RFM220 Measurement Demodulator.

A separate UI is provided to present the RFM220 measurements, enabling the user to monitor and analyze both Transport Stream and RF measurements simultaneously.

Both RF and ASI inputs can be connected to the RFM220 and the user can select the source for output to an MTM400A or any other device that requires ASI input. This enables monitoring before and after modulation.

Routing ASI Input.


Routing RF Input.

A unique feature of the RFM220 product is that it will continue to monitor the RF signal quality even if the ASI input is selected for routing to the MTM400A for TS analysis. In this configuration a 204-byte BTS input can be monitored providing TMCC and IIP consistency analysis in the MTM400A in addition to monitoring the RF broadcast signal quality.

ISDB-Tb RF Remote Monitoring Functionality (Alarms, Event Logs, and 7-day Trending of RF Metrics)

ISDB-Tb RF Remote Monitoring Functionality.

Key RF metrics including Channel Power, Full Band Power, SNR, MER, BER, Packet Error Ratio, and Shoulder Attenuation are monitored, tested, and displayed to enable operators to ensure that their RF systems are operating correctly and that services are available to viewers. Metrics and test results are stored and can be displayed as long-term trends for up to a 7-day history, as event logs for offline viewing, or exported into other tools for analysis and reporting. Remote access enables skilled engineers in broadcasters’ main engineering facilities to remotely diagnose problems at regional and local levels without the need to travel.

Overall and/or Separate MER per Layer (One for HDTV, One for the 1-seg)

The ISDB-Tb system provides hierarchical modulation whereby multiple services are broadcast as different layers within the same 6 MHz RF channel. Typically this consists of a low bit rate service using robust QPSK constellation on 1 of the 13 ISDB-Tb broadcast signal segments for mobile and handheld devices plus an HD signal using 64QAM on the other 12 segments. It is important for the operator to know the quality of the RF signal for each service. Products that only provide a single overall MER cannot distinguish between RF degradation issues that are affecting the mobile service and issues that affect the HD service.

MER Measurement Performance to 36 dB Typ.

MER is the key RF transmission metric used by broadcasters to ensure the transmission network is operating properly. High-quality MER measurements are critical to ensure that early indication can be given of transmission problems, enabling action to be taken before viewers’ reception of the signal is impacted. The quality of the RFM220 MER measurement means it is capable of being used as a remote transmitter monitor that will reliably give early indication of transmission issues, provide long-term trend information to alert operators of gradual degradations of signal quality, and take proactive action to prevent viewers from experiencing problems.

TMCC Information Monitoring

TMCC information must be monitored to ensure that receivers can demodulate the signal effectively. Errors in the TMCC information would lead to STBs not functioning properly. In addition to displaying the TMCC information on the RFM220 user interface, the MTM400A can be used to provide TMCC and IIP consistency testing and analysis at the Transport Stream layer. The in-depth ISDB-Tb cross-table consistency testing is a unique feature developed over many years in conjunction with Japanese broadcasters, and when combined with ISDB-Tb RF metrics the Tektronix solution represents a powerful and unique toolset for remote ISDB-Tb monitoring.

Channel Impulse Response Display and SFN Window Measurements

Channel Impulse Response Display and SFN Window Measurements.

The RFM220 provides Channel Impulse response graphs, (also known as Channel Delay Profile), over a 2x guard interval to show whether echoes caused by multipath are likely to cause interference problems. The five main echoes are indicated to the user to enable peaks to be easily identified, and the user can determine whether remedial action must be taken. This is particularly important in SFN networks where transmitters must be synchronized so they won’t interfere with each other, and the RFM220 displays can be used to remotely detect SFN network timing problems enabling corrections to be made.

Constellation and Spectrum Displays with Shoulder Measurements

Spectrum Displays with Shoulder Measurements.

The Constellation and Spectrum displays enable engineers to identify modulation problems such as amplitude imbalance, quadrature error, coherent interference, phase noise, amplitude noise, phase error, and MER problems. The left and right shoulder measurements are displayed in dB to help indicate if there are spectrum mask issues.

More information about identification of such problems using these displays is available in the Tektronix application note Critical RF Measurements in Cable, Satellite, and Terrestrial DTV Systems.

SNMP Trap Generation

The RFM220 monitoring system provides SNMP trap generation when tests fail, enabling the RF monitoring solution to provide notification to network management systems for operational alerting and reporting.