238 results about "Digital terrestrial television" patented technology

An HDTV receiver coupled to a terrestrial antenna displays real-time signal strength of terrestrial digital television signals. A graphical user interface preferably displays various data relating to all terrestrial television signals in a scrollable grid format. The grid is displayed within an active video display of a selected television signal from the grid. Audio for the selected channel is also active. A list of all channels tuned or selected is maintained to aid in searching. Channel lists are updated during certain channel searches.

The invention provides a device and a method for acquiring and optimizing the DTMB (digital terrestrial television multimedia broadcasting) single frequency network coverage rate, which is used for network planning and optimizing a terrestrial digital television single frequency network. The device comprises a station information processing module, a station database, a radio wave propagation budgeting module, an interference analyzing module, a calculation module, an optimization module, a GIS module, a geographic information database and a coverage result database. According to the invention, a synchronization threshold is defined so as to reflect the gain of the single frequency network, the active power and the interference power of a receiving plate are combined by adopting a K-LNM method, a correlation index of the combined active power and the combined interference power is solved by using a method of matching correlated matrixes, prediction of the place probability covering a community is enabled to consider the correlation caused by self-interferences and shadow fading of the single frequency network, and the place probability of a grid is calculated by using a CCDF function. The device and the method provided by the invention is more practical and more accurate in budgeting result, and small in calculation amount, enables the self-interferences of the single frequency network to be the smallest under the condition of not changing other parameters of a transmitter, and does not need to increase the cost.

A channel equalizer of a terrestrial digital TV receiver using a VSB modulation method is disclosed. By using a precise channel estimator according to the LS method, the transmission channel can be precisely estimated regardless of the characteristic of the transmission channel. By performing the channel equalization in the frequency domain based on the estimated channel, since the channel can be precisely compensated for, and a firm frame synchronization is supplied even to the time-varying multiple path channel, it can be exhibited superior performance even a mobile channel. Moreover, since the FFT implemented by hardware simpler than the transversal filter of the time domain can be used, the equalization is performed not the time domain but the frequency domain, a longer equalizing range can be obtained.

The invention discloses a power control based fast convergence adaptive method in an internet connection sharing (ICS) repeater. The method has the following advantage: an adjustable attenuator is installed behind a power amplifier of the repeater to control the output power. A power adjusting process comprises the following steps: (1) in the initial phase of echo cancellation, maintaining the attenuation value of the attenuator at the maximum betamax; (2) after maintaining the attenuation value at the maximum betamax for T1, gradually reducing the attenuation value, and adjusting the attenuation value by the attenuator once every T; and (3) when the attenuation value of the attenuator is adjusted to the minimum betamin, causing the power output of the repeater the reach the maximum and the system to enter into the stable working state. By the method disclosed by the invention, the transmitting power control technology can be introduced into the digital terrestrial television repeater, and is combined with the adaptive echo interference suppression technology, thus improving the convergence speed of the adaptive echo interference algorithm and effectively reducing the self-excitation risk of the repeater.

A transmitter includes: frequency conversion means for collectively frequency-converting terrestrial digital TV broadcast signals inputted such that the frequency of terrestrial digital TV broadcast signals of a viewing desired channel inputted by viewing desired channel input means, among the terrestrial digital TV broadcast signals inputted, are converted to a frequency of a specific unused channel of a predetermined VHF band; filter means for extracting only TV broadcast signals of the specific unused channel of the predetermined VHF band among the TV broadcast signals obtained by the frequency conversion means; and transmission means for amplifying and wirelessly transmitting the TV broadcast signals extracted by the filter means.

The invention discloses a digital emergency broadcasting host machine, which integrates and comprises an embedded industrial computer control center, a voice recording system, a client, a storage center, an IP data conversion module, a TS stream conversion module, an MP3 data conversion module, a database, a running memory, an encryption manager, a TTS text conversion module, a USB signal acquisition module, an audio signal acquisition module, an audio input module, a remote audio and data acquisition module, a microphone input, 4 GPRS modules, a display control system, a touch screen control and display module, a PID addressing control signal, a serial port control signal, high-low level control signals, an automatic priority level processor, a power supply, a volume detecting and adjusting module, a working state detection and display module, a satellite ground service center and a terminal data return module. An output end of the embedded industrial computer control center outputs a controlled power supply, audio and control signals of an IP network, terrestrial digital television broadcasting, RDS wired / wireless tuning, satellite and telephone / SMS / GPRS, and data to the satellite ground service center and switches to be connected with terminals.