HP Introduces Industry's First Test Solution for European Digital-Broadcast-Television Services
Hewlett-Packard is introducing a test solution to help European equipment manufacturers and broadcast-television operators develop, manufacture and install networks of high-quality digital-terrestrial broadcast transmitters. The new software extends the modulation-analysis capability of the HP 89441A vector signal analyzer to include digital video broadcast-terrestrial (DVB-T), allowing manufacturers and network operators to measure transmitter quality.
"Manufacturers and operators must be able to measure and specify digital-transmission equipment and trust their measurement results when activating new digital services," said Bill Savage, general manager of HP's Queensferry Microwave Division. "This latest application for our vector signal analyzer is the first commercial analysis product for European digital-terrestrial broadcast."
The analysis software provides consistent data that adheres to the recommendations of the DVB Measurements Group, an industry body that recommends measurement practices for digital television systems. DVB-T compliance helps ensure a common understanding of modulation quality regardless of transmission medium.
The HP 89441A vector signal analyzer, offers performance to 2.65 gigahertz, and can make all of the basic radio frequency (RF) measurements on the modulator or transmitter under test. It measures channel power and flatness, adjacent channel power and spurious emissions. The unit has built-in digital analysis that allows transmitter designers and manufacturers to measure several modulation formats with one instrument, from simple binary phase shift keying (BPSK) to complex formats such as quadrature amplitude modulation (QAM) and vestigial sideband modulation (VSB).
The software extracts data from the vector signal analyzer and displays the information in constellation diagrams. It measures the modulation-error ratio (MER) to give a quantitative result for modulation quality. The application also indicates equalizer response and plots modulation error by carrier, an aid to trouble-shooting during design and manufacturing.
DVB-T is the standard for digital-broadcast-television transmission accepted throughout Europe. It uses a modulation scheme known as coded orthogonal frequency division multiplexing (COFDM), a high-density, multicarrier environment chosen specifically to accommodate large single-frequency networks of broadcast transmitters and to combat the high probability of multipath interference expected in cities. The transmitted signal consists of a nominal 2 kHz or 8 kHz carrier within the 8 MHz bandwidth of a standard channel, with data modulated onto the carriers using low data-rate 16 or 64 QAM or quadrature phase shift keying (QPSK).