4 stars based on
The emergence of new systems for digital television broadcasting has been a tremendous growth of digital carriers in the bands broadcast television channels. Presently known equipment for measurement and signal analysis may be conveniently configured to measure signals both of analogical and digital nature.
To measure digital carriers are necessary procedures other than those required for measuring analog carriers. Identifying the carrier comprising the steps of: The system of the invention, as described, allows to automatically recognize if the signal being received is a digital or analog carrier.
This feature is notably advantageous for the purposes of the present invention as thus, the user should not make efforts to recognize what kind of carrier is present in a certain channel and therefore the signal processing, whether analog or digital, is performed more efficiently than with equipment for the same purpose have been used until now. In addition, according to the identification obtained from the carrier received, the system can automatically reconfigure the diferencias entre senales digitales y analogicas parameters of the instrument for measuring the carrier identified.
The equipment according to the invention comprises a controlled a microcontroller or microprocessor designed to perform certain automatic tunes within the channel assigned to the carrier in order to decide whether the carrier is present at that frequency is digital or analog circuitry; and a display unit or sound output that shows the user the result of the identification.
This output unit is also adapted to emit a signal to the user that can not be obtained an operational result. A measuring device thus conceived is able to recognize the signal to accurately measure the level or power of the carrier, which facilitates the task of the installer and allows faster and effective analysis as diferencias entre senales digitales y analogicas.
The identification system of the present invention is based on the basic feature that distinguishes a carrier with digital contents from a carrier with analogical content. In digital carriers, the transmitted energy is distributed homogeneously throughout the bandwidth of the channel. Instead, in a carrier whose content is analog, most of the energy is located at certain frequencies.
Measuring a digital carrier with a tuned receiver or a spectrum analyzer certain bandwidth is equivalent, without the appropriate decoder, to the diferencias entre senales digitales y analogicas of white noise in the whole measuring width. The system of the present invention is able to distinguish that the device is receiving "white noise" at a certain level above the measuring threshold within the channel bandwidth.
The Figure 1 is a block diagram in which schematically shows the steps defining a system for automatically identifying digital television carrier signals according to the present invention.
The Diferencias entre senales digitales y analogicas 2 is a graph of the voltage of a carrier relative to the digital television broadcasting frequency. The Figure 4 is a graph voltage-of a carrier modulated in FM analog diferencias entre senales digitales y analogicas.
The steps defining an identification system according to the invention are: An example of determining the nature of the received signals in a measuring instrument according to the identification system the invention is described below. The identification system that is given by way of non-limitative example corresponds to a system for the identification of carriers of digital television DVB-T transmitted within the UHF band and using allocated in said band according to the channel planning in the CCIR system channels.
In such a system, digital TV channels take up almost the entire bandwidth allocated to each channel 8MHz. The system used according to the present invention comprises a sequence of operations starting from the configuration 1 of a specific channeling system from which the channel distribution is known within the bands through which of the transmitting.
In other words, it comes to tuning the carrier frequency analog video as if the measuring equipment expected to find at that point an analog video carrier.
Then proceed to the reception or tuning 2 signal to the carrier frequency analog video, ie, the measuring equipment is prepared to receive an analog television signal.
The next step consists in analyzing the diferencias entre senales digitales y analogicas power according to the possible cases represented in the graphs of Figures 2, 3 and 4. Said analysis is based on the basic feature that distinguishes a carrier with digital contents carrier DVB-T digital television of a carrier with analogical content VSB-modulated carrier AM.
In digital carriers, the transmitted energy is distributed homogeneously throughout the bandwidth of the channel, as can be seen in Figure No. In contrast, in a carrier whose content is analog see Figures 3 and 4most of the energy is located at certain frequencies.
In the case of the spectrum of a carrier modulated analog television AM-VSB, the energy is located at the ends of the bandwidth see Fig Q 3. In this sense, the fact that an analog television terrestrial broadcasting, most of the energy transmitted is located at the carrier frequency video carrier chroma and audio carrier should take particular account. In short, with this step the system can recognize the way the energy of the carrier is distributed in the frequency band occupied by the channel.
This case is shown in Figure 1 by the reference numeral 5. The identification system continues at step designated by 7 in said Figure 1, where said measured level is calculated such increased frequency. Subsequently, similarly to step 4 described above, a step 8 comparing the result obtained in step 7 with the measured frequency of step 3 is made level.
The step of analyzing the received power can be summarized therefore in determining whether the measured level remains sufficiently constant within a certain frequency range. The identification system described allows automatically recognize whether the signal being received is a digital or analog carrier and therefore measuring equipment operating in accordance with the identification system will be able to recognize the type of signal received for proceed to accurately measure the level or carrier power, making it easy installer and allowing faster and more efficient analysis.
Thus, in the measurement process signal, diferencias entre senales digitales y analogicas it is an analog carrier, the device will measure its power by using appropriate filters and detectors. As stated, it needs to tune a channel type either present in the transmission system which is working for the measuring equipment to automatically identify the type of carrier that is receiving at a given time.
The measuring equipment includes means for determining the signal level, the field strength, spectrum analyzer, etc. The measurements can be obtained in a receiving circuit obtained carrier TV superheterodyne UHF band. The computer diferencias entre senales digitales y analogicas operates according to the identification system object of the present invention comprises a controlled by a microcontroller circuitry or a microprocessor adapted to carry out certain tunes within the channel assigned to the carrier diferencias entre senales digitales y analogicas order to decide whether diferencias entre senales digitales y analogicas carrier present in that frequency it is digital or analog.
Such equipment also includes an output unit visual or audible. More specifically, the output unit 12 shown in FIG n Q 5 includes an icon 13 informing the user that identified a carrier of analogical nature. The output unit 12 includes another icon 14as shown in Fig 6, to warn the user that a digital carrier has diferencias entre senales digitales y analogicas detected.
One of the icons 11 can also inform the user that no signal has been detected, as specified in step 5 described above in relation to Figure 1 of the drawings.
The failure to detected signal may be due to any limitations during the measurement process that may have caused can not reach an operating result, for example if the carrier level does not reach a certain predetermined threshold.
Although the identification system described is intended for the diferencias entre senales digitales y analogicas of carriers of digital television DVB-T transmitted within the UHF band and using allocated in said band according to the channel planning in the CCIR system channels, the identification system object of the present invention allows identifying CATV and DVB carriers.
Sufficiently described what the present invention consists in accordance to the enclosed drawings, it is understood that can be introduced in the same any detail modification as deemed appropriate provided that the essential characteristics of the invention are not altered, summarized in the following claims.
Diferencias entre senales digitales y analogicas of ref document: Kind code of diferencias entre senales digitales y analogicas document: The system automatically identifies whether a digital or analogic signal is being transmitted in the tuned channel by executing following frequency tuning steps 2: The device diferencias entre senales digitales y analogicas out automatic tuning to determine whether the carrier signal is a digital or an analogic carrier signal, said device also comprising an output unit 12 showing identification result.
EP EPA1 en System for analyzing noise signals in community antenna TV system return channel has spectrum converter with IF amplifier input connected to return channel input via filters and mixers.
Method for storing digital channel tuning data, and circuit, television receiver and video cassette recorder implementing the method. Apparatus for automatically detecting and playing desired audio segments over a broadcast receiver. System for providing signals from an auxiliary audio source to a radio receiver using a wireless link. Selection of traffic capable station by RDS radio while listening to other media. Radio receiver with switching circuit for elimination of intermodulation interference.
Apparatus and method for optimizing the level of rf signals based upon the information stored on a memory. Multiplex broadcast receiving apparatus and multiplex broadcast receiving method. Method for automatically searching a frequency range for signal channels in a receiver for digitally modulated signals, and receiver for applying such a method.
Tuning system with provisions for calculating the local oscillator frequency from an aft characteristic. Method and device for change of reception frequency in a digital audio broadcasting system receiver. A1 Designated state s: