Preliminary field tests results of ISDB-Tb digital TV transmission in the VHF-high band

Abstract

This paper presents preliminary results of field measurements carried out for evaluating the operation of the ISDB-TB standard digital TV in the VHF-high band. Measurements were performed in urban, suburban and rural areas in a medium-sized Brazilian city. The analysis includes results of static reception measurements for evaluating the received field strength and the signal to noise ratio thresholds for correct signal decoding. A comparison with theoretical values of field strength is also presented.

Experimental analysis of the signal-to-noise ratio of digital ISDB-TB TV receivers and multipath in the VHF-high band

“…The green dots indicate the sites with successful reception and the red dots indicate the sites with no reception. The C/N threshold was in the range of 15 to 18 dB [1]. However, in one site the reception was not successful and the C/N was 19.7 dB.…”

“…In this case, the reception failed due to the influence of multipath that caused great variability in the received signal. The received signal measured at this site was close to the field intensity threshold, which was in the range 46 to 48 dBμV/m [1], from Figure 5. The Recommendation ITU-R BT.1368-11 [11] presents a range of C/N values according to the configuration, for bandwidth 6 MHz in VHF-high band.…”

“…The noise power level was measured in the channel 13 at each measurement site, resulting in the median value of 28.37 dBμV/m [1]. The measured noise agreed to the theoretical values from the ITU-R Recommendation P.372-11 [13], which is 30.9 dBμV/m for a large city environment (in 213 MHz) and 26.6 dBμV/m for a residential environment (in 213 MHz).…”

“…In this way, the purpose of this work is to present the comparison between the signal-to-noise ratio values achieved from laboratory and from field tests in the VHF-high band [1], as a major contribution. The conducted experiment employed the methodology of noise injection until the receiver reaches the threshold of visibility (TOV) of image.…”

“…The digital television sets manufactured in Brazil since 2009 are able to operate in VHF-high band, aiming the future occupation of this band with digital TV broadcast. Considering the good performance of the field tests of ISDB-T B digital TV standard operating in VHF-high band performed in 2014 in Brazil, as described in [1], the use of this band with digital TV signals will be implemented. The broadcast of new digital TV channels in the referred band will be possible due to the switchover from analog to digital TV in Brazil, which will be gradually accomplished between 2016 and 2018.…”