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Signal analyzer DVB T
DVB-T (Digital Video Broadcasting – Terrestrial) is a standard for transmitting digital television signals over the air using terrestrial transmitters and antennas. It was developed to replace traditional analogue terrestrial television broadcasting with a more efficient digital transmission system.
DVB-T enables the transmission of multiple television and radio services within a single frequency channel. It provides improved spectrum efficiency, supports better picture and sound quality, and allows broadcasters to transmit additional information alongside audiovisual content.
Typical bandwidth used by DVB-T channel is 8 MHz.
DVB-T analyzer monitors DVB-T OFDM synchronization and equalized constellation quality.
DVB-T uses TPS (Transmission Parameter Signalling) carriers to describe mode, modulation, guard interval and code rate:
- FFT mode - detected DVB-T OFDM size, usually 2K or 8K.
- Guard interval - cyclic prefix ratio, for example 1/32, 1/16, 1/8 or 1/4.
- Modulation - detected constellation, for example QPSK, 16-QAM or 64-QAM.
- Code rate - forward error-correction code rate.
- MER - Modulation Error Ratio in dB. Higher is better.
- CP - cyclic prefix correlation; indicates OFDM timing lock.
- Pilots - pilot coherence; indicates how well continual/scattered pilots match expected positions.
- CFO - carrier frequency offset in Hz.
The constellation panel shows equalized DVB-T carrier points. Tight clusters indicate good demodulation. Wide clouds indicate low SNR, multipath, wrong bandwidth, bad tuning or overload.
Use a channel bandwidth wide enough for the selected DVB-T channel. For 8 MHz DVB-T, the I/Q analyzer should capture the full channel.