APPARATUS FOR RECEIVING TELEVISION, WIRELESS, MULTI CHANNEL SIGNALS
TECHNICAL FIELD The present invention relates to an apparatus for receiving television, wireless, multi-channel signals; and, more particularly, to an apparatus for receiving television signals, wireless, of multiple channels, which converts a signal with an MMDS band (multiple-point distribution service, of multiple channels) into a signal with a frequency band that is can see VHS / UHF (very high frequency / ultra-high frequency), identifies an address, which is used to identify a subscriber to a wireless television service, from the signal with a frequency band that can be seen, and performs the functions of conversion and disconnection of the frequency band, thus avoiding the illegal vision of CATV programs. TECHNICAL BACKGROUND Early CATVs were developed as an auxiliary means to assist users, who reside in restricted areas of general terrestrial broadcast television, to watch general terrestrial broadcast television. Recently, however, CATV programs are provided through a variety of channels, and
technologies are being developed to provide an interactive multimedia service in which the exchange of two-way information between users and a broadcast or broadcast station can be allowed. For a wireless CATV service capable of supporting such an interactive multimedia service that has been commercialized and is currently being developed, there are LMDS (local multipoint distribution service) and MMDS (multi-channel, multi-channel distribution service). The LMDS is a technology of transmission and reception of video, audio and general data between a transmitter of a broadcast service provider and terminals of the subscribers using a millimeter wave with a frequency band of 24-28 GHz, and is capable of provide a broadcast service for a relatively small cell with a radius of 2-4 km. In contrast, MMDS is a technology of wireless transmission and reception of multimedia data between a transmitter of a broadcast service provider and subscriber terminals using a signal with a frequency band of 2.5-2.7 GHz, and is able to provide a service through an area with a radius of 50-100 km. In general, each of the CATV subscribers who use MMDS is provided with a broadcast service to
through a reception system having a configuration as shown in figure 1. That is, when a TV signal is received through a reception antenna installed outside, the received signal is input to a converter-reducer 120. In this case, the received signal includes a signal with a frequency band of 2.5-2.7 GHz, and the eductor-converter 120 converts the frequency band of the received signal into a frequency band that can be seen, ie , a frequency band of several tens to several hundred Hz. A signal with the converted frequency band is input to a decoder 130. The decoder 130 amplifies, demodulates and / or decodes a part of the input signal, which has a frequency band corresponding to a channel selected by the subscriber, and provides the amplified signal, demodulated and / or decoded to a TV 140. In this case, the frequency band corresponding to the channel selected by the The user is set to a constant value, so that the decoder 130 previously stores the information of the frequency bands corresponding to several channels and performs a search function for channels that use the information. However, since a prior art receiving apparatus for receiving signals with an MDS band performs a search for a frequency band corresponding to
each of the channels based on fixed information, previously stored, frequency bands, a problem arises in that it is easy for users, who do not subscribe to the CATV broadcasting service, acquire such information of the frequencies and illegally see the CATV programs. DESCRIPTION OF THE INVENTION Therefore, an object of the present invention is to provide a multi-channel wireless TV signal receiving apparatus, which converts a MMDS frequency band into a frequency band that can be seen using a converter- reducer, locates the addresses to the subscribers for a CATV broadcast service to identify them, and performs the functions of the conversion and disconnection of the frequency band, thus avoiding the illegal vision of the CATV programs. In accordance with the present invention, there is provided a multi-channel wireless TV reception apparatus, including: a first converter-reducer for converting a signal with a first frequency band into a signal with a second frequency band; a second converter-reducer for converting a signal with the second frequency band into a signal with a third frequency band; a demodulator for the demodulation control data, which is used to control the TV reception apparatus, of the signal with the
third frequency band; a memory for storing variables related to the control of the TV reception apparatus; and a controller that converts a first reference frequency of the first converter-reducer using the control data output from the demodulator. The first converter-reducer of the multi-channel, wireless TV reception apparatus according to the present invention may include a first local oscillator for generating the first reference frequency; and a first mixer for generating the signal with the second frequency band by mixing the signal with the first frequency band and the signal with the first reference frequency generated by the first local oscillator. In addition, the second converter-reducer of the multi-channel, wireless TV signal receiving apparatus according to the present invention may include a second local oscillator to generate a second reference frequency; and a second mixer for generating the signal with the third frequency band by mixing the signal with the second frequency band and the signal with the second reference frequency generated by the second local oscillator.
The control data may include an instruction to convert the first reference frequency, and / or an ID (identification) of the subscriber. In addition, the controller can convert the first reference frequency of the first converter-reducer to a frequency displaced by a predetermined frequency quantity to the instruction for converting the first reference frequency. The controller can compare the subscriber ID with the variables stored in the memory, and stop the reception of the wireless signals in the multi-channel, wireless TV signal receiving apparatus, if the subscriber's ID does not match any of the variables BRIEF DESCRIPTION OF THE DRAWINGS The above objects and features of the present invention will become apparent from the following description of the preferred embodiments given in conjunction with the accompanying drawings, in which: Figure 1 is a diagram showing a converter-reducer of the prior art and a prior art decoder to receive a CATV signal;
Figure 2 illustrates a diagram showing an apparatus for receiving TV signals according to a preferred embodiment of the present invention; Figure 3 shows a circuit diagram showing a detailed configuration of the TV reception apparatus shown in Figure 2; Figure 4 depicts a flow diagram showing a method for controlling the TV reception apparatus according to the preferred embodiment of the present invention; Y
Figure 5 provides a diagram showing a format of a control data packet used to control the TV reception apparatus according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention are described in detail with reference to the accompanying drawings below. Figure 2 shows a configuration of a multi-channel wireless TV reception system according to a preferred embodiment of the present invention. A multi-channel wireless TV reception apparatus 210, in accordance with the preferred embodiment of the present invention is constructed to perform the functions of converter-reducer 120 and decoder 130 used in the
multi-channel, wireless TV reception system, shown in Figure 1. The TV reception apparatus 210 is connected to a 230 M DS antenna to receive signals with a MMDS frequency band (2.5-2.7 GHz), and a antenna 240 VHF / UHF to receive signals with a VHF band (54-216 MHz) / UHF (470-890 MHz). Accordingly, the TV reception apparatus 210 according to the present invention is constructed to receive both signals with a MMDS frequency band and signals with a VHF / UHF frequency band., but it can be connected only to the 230 MMDS antenna to receive signals with a MMDS frequency band. The TV reception apparatus 210 converts the frequency band of a signal received through the antenna 230 MMDS into a frequency band (VHF / UHF) that can be seen, and provides the signal with a frequency band that can be see for a TV 220. An AC power adapter 260 (alternating current) can be connected between the TV reception apparatus 210 and the TV 220 through a coaxial cable that employs BIAS-T, and functions to supply power to the apparatus 210 of TV reception. In addition, the TV reception apparatus 210 performs the additional frequency conversion to extract a signal from a frequency band, which includes the control data transmitted from an integrated CATV management center, from the signal with a band (VHF / UHF). ) of frequency that
can see, converted from the signal with a MMDS band. The TV reception apparatus 210 performs the functions of verification of subscriber ID, conversion and disconnection of the. frequency band that uses the extracted control data. Fig. 3 is a circuit diagram showing the detailed configuration of the TV reception apparatus 210 shown in Fig. 2. The configuration of the TV reception apparatus 210 shown in Fig. 3 will be described in detail below. First, the TV reception apparatus 210 performs a first conversion-reduction step in an RF signal (radio frequency) received through the 230 MMDS antenna shown in Figure 2. That is, the RF input signal is inputted. to a bandpass filter 303, and only a portion of the input signals, which have a frequency band MMDS, is passed through it and amplified by an amplifier 304. Although in FIG. 3, only the bandpass filter 303 and amplifier 304 have been illustrated as existing between the input terminal for the RF signal and a mixer 305, various types of filters or amplifiers may be included therebetween, according to a radio environment within a range that does not influence the standards of
figures or amounts of noise and other electrical characteristics. Meanwhile, the memory 328 stores programs and data used to perform the functions of subscriber ID verification, the conversion and disconnection of the frequency band, and a CPU (Central Processing Unit) 327 performs the functions of ID verification of the subscriber, the conversion and disconnection of the frequency band by executing the programs stored in the memory 328. In addition, the CPU 327 controls a PPL (circuit engaged in the phase) 325 to generate a constant tuning voltage by providing a control signal to the PLL 325, and PPL 325 causes a first local oscillator 308 or a second local oscillator 324 to generate local oscillation signals with specific frequencies by providing the constant tuning voltage to the first local oscillator 308 and the second local oscillator 324. In an initial stage, the first local oscillator 308 is controlled to generate a signal with a first frequency fl, for example, 1889 MHz, if necessary, it can be controlled to generate a signal with a second frequency f2, for example, 1892 MHz , the first frequency fl shifted by a frequency band of 3 MHz. After the first local oscillator 308 is set to generate the signal with a second frequency f2, the first local oscillator 308 can be adjusted
to generate the signal with the second frequency fl through the frequency conversion of 3MHz, if necessary. 3 MHz, which is a frequency difference for the frequency conversion, corresponds to one half of a difference between the center frequencies of two adjacent channels of a CATV currently used, and is a value adjustment to prevent users from illegally viewing the CATV programs. The frequency difference for the frequency conversion may vary depending on a radio environment where the TV reception apparatus of the present invention is used. The signal generated in the first local oscillator 308 is provided to the mixer 305. The mixer 305 mixes the output signal of the amplifier 304 with the output signal of the first local oscillator 308, thus forming a signal with an IF (intermediate frequency) (per example, if fl = 1889, IF is 608-800 MHz), and provides the signal with the IF to an attenuator 312. The signal input to the attenuator 312 is amplified by an amplifier 313, and the amplified signal is provided to the TV 220 as an audio / video signal. Although not shown in Figure 3, a filter and an amplifier can be placed between the mixer 305 and the attenuator 312 to filter the unnecessary high frequency components, which can be generated when two signals are mixed together in the mixer 305.
Meanwhile, although not shown in FIG. 3, a signal received through the antenna 240 VHF / UHF can be input directly to the TV 220 in the form of a signal with an IF in which the conversion-reduction of first stage described above is not carried out. In the meantime, the output signal of the mixer 305 includes the control data, which will be used to carry out the functions of verification of the subscriber ID, frequency conversion and disconnection, as well as an audio / video signal, the which will be supplied to the TV 220. Accordingly, a second stage of the reduction conversion is required to extract such control data. To extract such control data, a coupler 329, an amplifier 315, a mixer 317, the second local oscillator 324, a bandpass filter 318 and an amplifier 320 are included in the circuit shown in Fig. 3. The coupler 329 extracts a carrier with a specific frequency (e.g., 650.14 MHz), which includes the control data, from the output signal of the mixer 305, and provides the bearer to the amplifier 315. The signal provided to the amplifier 315 is amplified and is input to mixer 317. mixer 317 mixes a signal with a specific local oscillation frequency (eg, 639.44 MHz) provided from the second local oscillator 324 with the
signal produced from the amplifier 315, thereby generating a signal with a specific frequency (e.g., 10.7 MHz), which includes the control data. The signal generated in the mixer 317 is input to a demodulator 322 through the passband filter 318 and the amplifier 320. In this case, the carrier that includes the control data is a frequency modulated signal before transmission to a transmitter, so that the bearer undergoes demodulation, which is an inverted conversion of the frequency modulation, in the demodulator 322, and the data obtained through such demodulation is input to the CPU 327 and used for verification of a subscriber ID and control of the PLL 325. In the following, a method for controlling the TV receiving apparatus according to a preferred embodiment of the present invention will be described in detail. Fig. 4 is a flow chart illustrating a method for performing the functions of verifying subscriber ID, frequency band conversion and disconnection through the use of the TV receiver apparatus 210 shown in Fig. 3. First, the CPU 327 starts the variables related to the operation of the TV receiver apparatus 210 (step 402). In this initialization stage of variables, the CPU 327 establishes a period (for example, 230 μß) for which
examines whether the control data is input, a value of the initial frequency of the first local oscillator 308 (eg, 1892 MHz), and a value that indicates the ON / OFF of the disconnect function (eg, OFF). Then, the CPU 327 controls the PLL 325 to generate a tuning voltage corresponding to the value of the initial frequency of the first local oscillator 308 (step 404). Consequently, the PLL 32E controls the first local oscillator 308 to generate a local oscillation frequency identical with its initial frequency. Then, the CPU 327 performs steps 402 and 404 as described above, the initialization steps of the method for controlling the TV receiver apparatus and the control method according to the present invention are completed. Then, while steps 406 to 420 are carried out repeatedly, which will be described in detail in the following, the functions of frequency band conversion, disconnection and verification of the subscriber ID according to the present one are carried out. invention. That is, the CPU 327 examines whether the control data has been input to the demodulator 322 (step 406). Once the control data has been input to the demodulator 322, the control data is read into the memory 328 or a buffer of the CPU 327 (step S408). Also I know
it checks whether the control data read in the memory 328 or the buffer memory has a format in accordance with a given protocol (step 410). For example, in the method for controlling the TV receiver apparatus 210 according to a preferred embodiment of the present invention, a control data packet having a format, as shown in FIG. 5. In the control data packet shown in FIG. 5 the field < STX > , the field < GROUP > , the field < ADDRESS > , the field < CMD > , the field < ETX > and the field < BCC > . Among these fields, the field < STX > it can include a unique value, for example, "FDh" indicating a header of the control data packet. Accordingly, the CPU 327 determines whether a signal input from the demodulator 322 is a control data packet having the format according to the present invention, comparing the value of the < STX > with the value previously stored in memory 328 or the like. The field < STX > indicates the type of control data. For example, when the value of the field < GRUP0 > is "Aah," you can recognize that an instruction currently included in the < C D > is the instruction "3MHz frequency conversion". Also, in the < ADDRESS > of the control data packet, a subscriber ID transmitted from the
management center integrated to the CATV. The CPU 327 determines whether a user currently using the TV receiver apparatus 210 is illegally viewing the CATV programs, comparing the value of the < ADDRESS > with the values previously stored in memory 328 or the like. The management or administration center integrated with the CATV transmits all the IDs of the current individual or subscriber groups periodically or when necessary to prevent illegal viewing. The TV receiver apparatus 210 determines whether the transmitted IDs have identical values with the existing values previously stored. If the value of the field < ADDRESS > it does not match any of the values previously stored in the memory of the TV receiver apparatus 210, this may determine that the user is illegally watching a CATV program. The field < C D > The control data package includes an instruction that the CPU 327 can execute immediately. The meanings of the respective bits of the field < CMD > are shown in Table 1. < Table 1 > Meanings of the respective bits of the CMD field
In Table 1, the error verification bits (bit numbers 2 and 3) are used to verify an error of the data packet of the received control, being compared with the specific bits (for example, the numbers of bits 1 and 5). ). The header end data (bit numbers 4-7) are not currently used, and are reserved for the addition of other functions later. The field < ETX > of the control data packet includes a unique value, for example, "FEh" to indicate the end of the control data. Finally, the field < BCC > includes a bit value to examine if an error has occurred in the control data. For example, the examination of whether an error of the control data has occurred can be carried out as follows. That is, the value of the field < BCC < it is compared with a value obtained by adding or subtracting a value, which is obtained by adding all the values of bits that vary from the field < GRUP0 > to the field < CMD > , or from a value, which is obtained by carrying out an XOR operation between the field values < STX > and the field < ETX > . In this case, if the two values coincide with each other, it can be determined that an error has not occurred. If the two values do not coincide with each other, it can be determined that an error has occurred. If the signal produced from the demodulator 322 is a control data packet as described above, it is
determines whether a current instruction indicates frequency conversion of 3 MHz, by examining the < CMD > of the received control data packet (step 412). If the current instruction indicates the frequency conversion of 3 MHz, the CPU 327 transmits a control signal to the PLL 325 so that the local oscillation frequency of the first local oscillator 308 can be converted to a value (f2) shifted from the current value fl at 3 MHz (step S414). In addition, the PLL 325 controls the first local oscillator 308 to generate the signal with the converted frequency f2 in response to the control signal from the CPU 327. As described above, 3 MHz, which is the frequency conversion value , it can vary to different values depending on the radio environment where the TV receiver apparatus 210 is used. Then, the CPU 327 compares the value of the field < ADDRESS of received control data packet with the subscriber ID values previously stored in memory 328 (step 416). In this case, a case where any of the previously stored subscriber ID values does not match the value of the < ADDRESS > of the received control data packet indicates that the person is an illegal bystander, so that the user of the TV receiver apparatus 210 must be warned that he is illegally watching a CATV program, performing the disconnection function if it is
necessary. Accordingly, the CPU 327 determines whether the currently received instruction indicates execution of the disconnect function, by examining the < CMD > of the received control data field (step S418). When the CPU 327 determines whether the shutdown function is performed, the CPU 327 examines the second bit (bit number 1) of the < CMD > of the received control data packet as illustrated in Table 1. That is, if the value of the second bit of the field < CMD > is "0", the disconnection function is not carried out. On the other hand, that is, if the value of the second bit of the field < CMD > is "1", the disconnection function is carried out. Accordingly, if the value of the second bit of the field < CMD > is "1", the CPU 327 carries out the disconnection function, thus preventing the user from viewing the CATV. The disconnection function can be carried out by controlling the attenuator 312 to reduce the intensity of the signals that are introduced to the TV 220, so that the TV does not detect any signal to be introduced in it. In contrast, if the value of the field < ADDRESS > and the previously stored subscriber ID match one another in step 416, or if, as a result of the examination of the field value < CMD > , the disconnection function is off, it is not necessary to carry out the disconnection function. Therefore, the CPU 327 repeatedly performs steps 406 a
420 without performing the disconnection function. As described above, the present invention provides the TV receiver apparatus and the control method thereof, which is capable of preventing the illegal display of the CATV by performing the verification functions of the subscriber ID. Frequency conversion and disconnection using a control data packet transmitted from the integrated management center to the CATV. While the invention has been shown and described with respect to the preferred embodiments, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.