Digital Terrestrial Television Signals Research Articles

Statistical analysis of atmospheric parameters, noise temperature and digital terrestrial television signal strength over Jos metropolis, Plateau state, Nigeria

The study of the relationship between the Received Signal Strengths (RSS) from Unity TV (786 MHz) located at Rayfield (9.84 o North 8.89 o East), Jos, Plateau State and some atmospheric parameters with noise temperature has been done using two years half-hourly data. The measurement was carried from 5 am and 9 pm daily. The analysis was carried out using the regression, co-integration and Granger causality models. The results show that the RSS is higher in the morning hours (5.00 am–9.00 am) late in the evening (6.30 pm–9.00 pm) but lower between 9.00 am and 6.30 pm. This might be due to the “dusty” atmosphere and low reflection of ionosphere in the day time which causes signal attenuation within the day time. The correlation coefficients from the coefficient of determination (R squared) of 0.88, 0.004, 0.838. 0.25, 0.867, and 0.112, are −0.94, −0.07, 0.92, −0.50, −0.93, −0.334 for atmospheric temperature, pressure, relative humidity, wind speed, noise temperature and rainfall respectively. It means all the independent variables except relative humidity are inversely proportional with the RSS. Also, the higher R2 values for atmospheric temperature, relative humidity and noise temperature respectively, indicates higher correlation between RSS and these parameters. It can be inferred that the models are suitable for predicting Unity TV (UTV) signal strength and that of other TV stations in Jos and environs, using T, RH and NT as inputs. The results also showed that there is a co-integration and Granger Causal relationship between the parameters and RSS.The result will find applications to the Nigeria Broadcasting Commission in the assigning of frequencies taking atmospheric parameters into considerations, Radio Engineers and Scientists, Satellite link designers, and mobile communication experts for the link budget design and appropriate equipment deployment based on the atmospheric condition on the geographical areas.

Preliminary performance evaluation and verification of digital terrestrial television signal propagation

This article presents the computer simulation and field test measurement results on Channel 29 for the preliminary performance evaluation and verification of the newly-installed Lesotho digital terrestrial television network based on DVB-T2 standard following the guidelines and techniques specified by the ITU-R BT.2035-2. It evaluates, at predetermined outdoor locations for fixed and mobile reception, parameters such as received signal strength, signal quality, bit-error rate (BER) and threshold-of-visibility (ToV) together with TV signal decoding (observation of screen artefacts) for quasi error-free reception. The results indicate that at over 97% of the test sites/points at the university town of Roma, the main Berea Plateau transmitter from the capital city (Maseru) broadcasts digital television service with enough signal level and quality to be properly decoded. The measured signal strength threshold ranges above -50 dBm for good reception, -64 dBm to -50 dBm for acceptable reception and -69 dBm to -64 dBm for poor reception. With the noise floor at about -73 dBm, the minimum required C/N of around 23 dB for good reception and about 4 dB for ToV have been recorded. The relative values of minimum required respective signal strength and signal quality for ToV obtained from the set-top box are 33% and 18% for stationary reception, while they give 37% and 20% for mobile reception.

Modeling digital terrestrial television signal strength with atmospheric parameters and noise temperature: a case study of North-Central Nigeria

The modeling of DTTV signal strength (AIT, NTA, ETV and Channels TV) in Abuja and Unity TV, Jos, Plateau State, with atmospheric parameters (temperature, pressure, relative humidity, wind speed and rainfall) as well as noise temperature, from April 2019 to December 2020 have been carried out using the atmospheric parameters measured with an automatic weather station and noise temperature measured with a non-contact infra-red thermometer, with TV signal strength measured with a CATV signal strength meter from 5.00 am – 9.00 pm daily, at 30 minutes interval. The results show that atmospheric temperature (58%), noise temperature (60%) and atmospheric pressure (100%) affect the Received Signal Strength (RSS) negatively, while the wind speed (60%), relative humidity (80%), and rainfall (100%) affect the signal strength positively. The RSS measured in Jos on altitude 1,400m was higher than that in Abuja on altitude 470m which may likely be due to an increase in altitude resulting in a decrease in atmospheric pressure and air density which implies less signal attenuation. It can be inferred that atmospheric parameters and noise temperature have a great impact on the RSS in the study areas. Consequently, the higher signal received in the rainy season compared to the dry season may be due to less dust in the atmosphere as well as the enhanced digitalized television signal and its robustness to interference and signal attenuation compared to the analogue signal. The developed models have low RMSE values; hence will be able to predict the influence of atmospheric parameters on TV RSS in the areas. Generally, the result will be useful to the Nigeria Broadcasting Commission to improve the quality of the signal transmission of digital television broadcasting for the future digital switchover in other parts of the country especially on the choice of antennas on their transmitters. The findings will also be useful to spectrum users such as mobile telecommunication, wireless internet, and radio broadcasting in managing and improving the quality of their services.

Impact Of Atmospheric Parameters And Noise Temperature On Digital Terrestrial Television Signal Strength Overkarshi Area, Abuja, North-Central, Nigeria

In this paper, the impact of atmospheric parameters (atmospheric temperature, pressure, relative humidity and wind speed) and noise temperature on digital terrestrial television signal strength over Karshi area, Abuja, North-Central part of Nigeria has been examined. Measurements were taken for a period of nine months (April 2019 – December 2019) to cover the commencement of rainy period and towards the end of rainy period. The results showed that atmospheric and noise temperature as well as wind speed weakly influenced the signal strength while relative humidity strongly influenced the signal strength. The effect of atmospheric pressure over the signal strength was not consistent during the period of measurement. The signal strength of AIT, NTA, Channels TV and ETV were negatively affected by the atmospheric temperature up to about88.8%, 25.6%, 16.5% and 93.2%, respectively; the noise temperature up to about 85.3%, 13.4%, 5.9% and 90.7% respectively and wind speed by about 89.2%, 26.8%, 16.3%, and 92.4%respectively. However, the signal strength was affected positively by the relative humidity up to about 87.9%, 18.7%, 10.1% and 92.4% respectively, while the atmospheric pressure affected NTA and Channels TV negatively by about 21.3% and 26.8%, respectively and affected AIT and ETV positively by about 22.7% and 26.8%, respectively. Findings from this study will be of help to satellite link designers, policy makers, antenna modelers and other TV transmission equipment designers on how to mitigate the effect of some of the atmospheric components on digital terrestrial signal strength reception in Nigeria.

Design and Testing of Fractal Antenna Parameters based on the Koch Curve for Reception of Digital Terrestrial Television Signals in the UHF Band

Purpose – In this research paper, the electrical and radiation characteristics of a proposed fractal antenna based on the Koch curve in the second iteration for reception of digital terrestrial television signals are designed and analyzed by laboratory tests.
 Methodology/approach/design – The design is based on the concepts of fractal geometry and on a previously designed antenna, which is adapted to obtain a different frequency of operation; the designed antenna is constructed in three different ways, finally, they are tested in the lab using vector-network-analyzer, that allows to measure parameters, such as: VSWR, gain and radiation pattern.
 Findings – The fractal antenna based on the Koch curve has the necessary characteristics to receive digital terrestrial television signals in the UHF band.

RECOGNITION OF PROPELLER-DRIVEN AIRCRAFT IN A PASSIVE BISTATIC RADAR

Nowadays passive bistatic radars (PBR) allow for detection, determination of coordinates and tracking of moving objects. In order to enable PBR integration into air traffic control systems, it is necessary to solve the problem of recognizing airborne objects, in particular, propeller-driven aircraft (AC). This will increase the degree of aviation safety. To solve the recognition problem, the analysis of propeller-driven aircraft echo signals, such as helicopter and propeller airplane, is performed. The in-formative features that can be used for recognition of propeller-driven aircraft in PBRs are defined. The method for propeller-driven aircraft recognition is proposed, that is based on extraction of modulation components originated from the rotational parts of the aircraft and estimation of their rotation parameters. The algorithm for echo signal processing is developed, which makes it possible to apply the proposed recognition method for PBRs. The experimental results of the processing algorithm are presented on the example of real signals reflected from the Mi- 8 helicopter and the Cessna 172 propeller aircraft. The experimental data are recorded by two different PBRs using DVB-T2 digital terrestrial television signals standard for airspace illumination. The estimated rotation parameters of the aircraft propeller blades correspond to the actual values. Such a correspondence allows not only to recognize the aircraft group, but in some cases to identify its type.

Analysis of propagation models for digital terrestrial television (DTT), under the ISDB-Tb standard in cities of Ambato and Latacunga, Ecuador

Most countries in South America have adopted ISDB-Tb as a standard for Digital Terrestrial Television broadcasts. In some countries, the deployment is in the early stages. However, the unique conditions of the South American countries have not taken into account the selection of the propagation model used for the unbundling of new DTT networks. Ecuador has adopted the ISDB-Tb for DTT transitions, which optimizes the radio spectrum and implements new audiovisual and interactive services. At present, DTT signals are being tested in the cities of Ambato and Latacunga. For the successful implementation of DTT in the Andinos countries, it is necessary to select the propagation model that best suits the propagation conditions of the region. The present study determines the model of propagation that best adjusts to the conditions of propagation of the cities under study through eld measurements. The selection of cities is relevant in the sense that they have geographic and climatological characteristics similar to those of other cities in the Andean region, so the results can be extrapolated to other cities in the region. The model of propagation that best fits the geographic conditions of the region was model ITU-R 525/526.

Spectrum Sharing for LTE-A and DTT: Field Trials of an Indoor LTE-A Femtocell in DVB-T2 Service Area

In the near future, many applications such as environmental sensors, smart objects, health sensors, and personal devices will be connected to mobile networks requiring additional spectrum. Studies have been made to demonstrate a low occupancy time and locations on the digital terrestrial television (DTT) band. This available or unused spectrum have been called “TV-White-Spaces.” In the 2015 World Radiocommunication Conference, the ITU decided to re-allocate the 700 MHz band (694–790 MHz) for International Mobile Telecommunications (IMT) services and also emplaced the discussion of the future use of the DTT band (470–694 MHz) to 2025, for which studies have been requested. In this paper, we study a particular case which goes a step beyond the previous ones, as it aims at sharing the same frequency band in the same area between long term evolution—advance (LTE-A) and digital video broadcasting—terrestrial second generation (DVB-T2) technologies. Those geographical areas that are not covered because the useful DTT signal is obstructed by the environment or it has a limited coverage by the network design can be called “micro-TVWS.” We assume that a DVB-T2 transmitter provides coverage for fixed rooftop reception as a primary service, to a building in which a LTE-A femtocell is installed indoors for local coverage, as a secondary service. The results have been obtained by laboratory emulation and validated through field measurements using professional equipment. Our results provide the technical restrictions of the LTE-A femtocell, mainly on the maximum allowable effective isotropic radiated power that could transmit on the DTT band in terms of carrier separation, from co-channel to adjacent band. These results meet the need of spectrum for IMT-Advanced technologies, so spectrum sharing is proposed in this paper as a new solution to make an efficient use of this resource.

Interference Analysis Between Digital Terrestrial Television (DTT) and 4G LTE Mobile Networks in the Digital Dividend Bands

With the introduction of digital terrestrial television (DTT) and the analogue television switch-off, terrestrial broadcast spectrum in the UHF band is being released for mobile communications, in particular for fourth generation (4G) long term evolution (LTE) mobile services. This spectrum is known as digital dividend. An impending problem when deploying 4G LTE mobile networks in the digital dividend bands is that interferences may appear in the adjacent radio frequency channels used for DTT. In this paper, we analyze the adjacent coexistence of DTT and 4G LTE networks in the digital dividend bands at 700 MHz and 800 MHz. A generic framework is adopted such that results can be easily extrapolated to different scenarios and bands. Results are presented as a function of the guard band between technologies, for both LTE uplink and downlink adjacent to the DTT signals, and for fixed outdoor and portable indoor DTT reception. Also, the effect of using anti-LTE filters is studied.

Experimental investigation of accuracy time-frequency synchronization by using digital television signals

The results of studying the model of passive time-frequency synchronization system are given in the paper. The algorithm of general coverage is taken as a basis. Brief description and mathematical analysis of the algorithm of general coverage were conducted. The laboratory bench, used in this work was described. Digital terrestrial television signal is used as a general signal source. Correlation and spectral signal properties of the digital terrestrial television were shown. Sources of errors, arising in the receive and signal processing paths and their influence were estimated. An algorithm for digital processing of measurement results of scale shifts was developed. It includes spectral analysis, correlation processing, as well as mathematical methods, allowing to improve the scale difference calculation accuracy. The results of experimental investigations and their statistical analysis are shown. The graphs and bar charts, showing statistical processing results, which reflect positive trends for using the digital terrestrial television signal as a common source for comparison of time and frequency scales according to the algorithm of general coverage.

An EIA/CEA-909 Compatible Smart Antenna System for Digital Terrestrial Broadcasting Applications

This paper discusses the theory and design of a smart antenna system for receiving digital terrestrial television signals. The pertinent antenna theory and the associated hardware is presented as is the relationship between the two. Finally, field results using digital terrestrial television signals are presented to evaluate the performance of the smart antenna system.

A DTV reception technology using software data streaming on a personal computer

This paper describes a new DTV (digital terrestrial television) reception technology relying primarily on software to receive, process and display DTV signals, which realizes an integrated DTV reception add-on card, and real-time MPEG-2 data streaming by software on a PC (personal computer). In addition to the real-time DTV reception, this technology can be also applied to a HDD (hard disk drive) based video recorder with time-shift function, where the DTV signal is stored onto the HDD and played back. Utilization of PC assets enables cost-effectiveness and rich functionality.

Adjacent and co-channel interference disturbances from a digital terrestrial television signal (COFDM-8K system) on analogue PAL systems

This paper presents some results of a measurement campaign in the service area of the digital terrestrial television (COFDM-8K system) experimental network of Madrid (Spain). The purpose of this survey has been to determine the degradation suffered by analogue PAL-G signals in the presence of co-channel and adjacent channel digital emissions. The result is a curve that estimates the protection ratios between analogue and digital received power levels.

Measurement and characterisation of distortions in the digital terrestrial television channel

This paper reviews distortions present in the received digital terrestrial television signals and presents a measurement campaign for the development of suitable RF channel models. These are necessary for the development of demodulator devices that are well optimised for high performance at low cost, since the performance of synchronisation and equalisation sub-systems are critically dependent on the distortions in the channel.

Local-area field strength variation measurement of the digital terrestrial television signal (COFDM 8K) in suburban environments

This paper presents the results of a field measurement campaign at the experimental COFDM 8K digital terrestrial television network developed by the partners of the VIDITER project in Madrid (Spain). This article focuses on the field strength spatial variation distribution inside small coverage areas. Due to the fact that the distribution parameters strongly depend on the survey area type, during this first stage the only environments taken into account have been those traditionally considered as suburban.