US 6,480,551 B1 · Signal processing device and method for switching signal processors thereof

Abstract

A digital broadcast program broadcast with a first network is transmitted to a second network. A tuner 41 selects digital broadcast signal having a predetermined transmission frequency and ECC decoder 43 obtains MPEG2 TS packet S3 as the digital broadcast data on the digital satellite broadcasting. An NIT detecting circuit 44 detects NIT from the MPEG2 TS packet S3 and a control unit 31 changes the NIT to obtain a table NITb applicable to CATV. A NIT substitution circuit 48 detects NIT from the MPEG2 TS packet S3 and substitutes table the NITb for the NIT to obtain MPEG2 TS packet S4 as the digital broadcast data on the CATV. Then, an error correct code is added to the MPEG2 TS packet S4 and the added packet S4 is modulated. Then, modulated one is frequency-converted to obtain digital broadcast signal BS-1 having a predetermined transmission frequency for the CATV. Further, a signal processing device including spare (redundant) signal processors simplified in their configurations and simple in their management may be obtained by this invention. Switch units corresponding to N signal processors in use, of switch units 33-1 through 33- (N+1) are brought into conduction, and the switch unit corresponding to the remaining one signal processor set as a spare and placed in a standby state is brought to a cut-off state. Signals outputted from the switch units 33-1 through 33- (N+1) are added together and the result of addition is sent to a CATV transmission path 13. When any of the N signal processors in use fails and a user inputs information about its failure through an operation unit 35, the faulty signal processor is newly kept in reserve and standby state. As an alternative to this, each signal processor kept in reserve and standby state up to now is placed in a used state. Thereby, it is possible to construct a spare signal processor as being unfixed.

Claims14

Dependent claims

A signal processing device for converting a first digital broadcast signal having a predetermined transmission frequency on a first network into a second digital broadcast signal having a predetermined transmission frequency on a second network comprising:

demodulating means for demodulating a first digital modulated signal, based on said first digital broadcast signal, to obtain digital broadcast data;
table-detecting means for detecting a table, including physical information relating to a transmission path, from said digital broadcast data obtained by said demodulating means;
table-changing means for changing said table detected by said table-detecting means so that the table is applicable to said second network;
table substitution means for substituting the table changed by said table-changing means for the table of said digital broadcast signal obtained by said demodulating means;
modulating means for modulating said digital broadcast data and the substituted table to obtain a second digital modulated signal;
and
frequency-converting means for frequency-converting said second digital modulated signal to obtain a second digital broadcast signal.

4 more elements

A signal processing device comprising:

a plurality of signal processors including at least one spare signal processor, wherein at least two of said plurality of said signal processors, other than said spare signal processor, process signals on a parallel basis;
a switch unit for determining whether an output signal is output from each of said plurality of signal processors;
and
switching control means, operable when one of said plurality of signal processors fails, to switch said spare signal processor to process said signal in place of said signal processor that failed;
wherein each of said plurality of signal processors respectively includes:
tuner means for selecting a first digital broadcast signal having a predetermined transmission frequency from a plurality of digital broadcast signals on a first network and thereby obtaining a first digital modulated signal;
demodulating means for demodulating the first digital modulated signal to obtain first digital broadcast data;
program specific information changing means for changing program specific information about the first digital broadcast data to program specific information suitable to a second network to obtain second digital broadcast data;
modulating means for modulating the second digital broadcast data to obtain a second digital modulated signal;
and
frequency-converting means for frequency-converting the second digital modulated signal to obtain a digital broadcast signal having a predetermined transmission frequency on the second network.

8 more elements

A switching method for switching signal processors suitable for use in a signal processing device, said signal processing device having a plurality of signal processors respectively including tuner means for selecting a first digital broadcast signal having a predetermined transmission frequency from a plurality of digital broadcast signals on a first network and thereby obtaining a first digital modulated signal;

demodulating means for demodulating the first digital modulated signal to obtain first digital broadcast data;
program specific information changing means for changing program specific information about the first digital broadcast data to program specific information suitable to a second network to obtain second digital broadcast data;
modulating means for modulating the second digital broadcast data to obtain a second digital modulated signal;
and frequency-converting means for frequency-converting the second digital modulated signal to obtain a digital broadcast signal having a predetermined transmission frequency on the second network;
and a circuit for processing said signals output from said tuner means, said method allowing each of said plurality of signal processors, other than a spare signal processor, to process a broadcast signal having a predetermined transmission frequency,
said switching method comprising the steps of:
switching said spare signal processor in place of a failed signal processor for processing the broadcast signal having a first transmission frequency;
designating said failed signal processor as a spare signal processor;
setting said tuner means of said spare signal processor to said first transmission frequency;
and
setting a processing state of said processing circuit included in said spare signal processor to coincide with a processing state of said processing circuit included in said failed signal processor, and thereafter switching said spare signal processor in place of the failed signal processor for processing the broadcast signal having said predetermined transmission frequency.

8 more elements

Dependencies are inferred from the claim text.

Signal processing device and method for switching signal processors thereof

Life of this patent

Signal processing device and method for switching signal processors thereof

Life of this patent

Abstract

Claims14