Television – Format – Including additional information
Reexamination Certificate
1998-06-01
2001-07-24
Kostak, Victor R. (Department: 2611)
Television
Format
Including additional information
C348S474000, C348S470000
Reexamination Certificate
active
06266096
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method of encoding digital data of arbitrary data rates of at least one data signal for jointly transmitting the encoded data with a digital picture signal, and to a digital data encoder for encoding such data.
2. Description of the Related Art
Together with analog television signals, additional data are transmitted for different purposes. These data may be, for example, teletext data which are transmitted in given picture lines of the television signal. These days, for example, data bits for signalizing the format of the television signal (4:3 or 16:9) are additionally transmitted. Internationally, different data formats are transmitted at different data rates and different bandwidths in predetermined picture lines of the television signal.
There may be a desire to insert such data, which are not normally present in a picture signal, into such a signal so as to apply them, for example, to a digital encoder which converts the digital picture signal into an analog picture signal. For this purpose, the laws in the analog world relating to bandwidth limitation, signal shapes, clocks, etc., are to be adhered to after conversion of the data signal into an analog signal. However, these laws may be different for the different types of data.
Known data encoders provided for this purpose have with the problem that they are not switchable to different data rates and data formats. Consequently, individual data encoders must be provided for the different data formats. A multitude of data encoders must therefore be provided for data signals of different formats to be possibly inserted into a digital picture signal.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a data encoding method and a data encoder which allow insertion of data of different formats, bandwidths and clock rates into a digital picture signal.
According to the invention, this object is achieved in a method of encoding digital data in that, in the encoding of the data, at least parts of the edges of data bits of the data signal are replaced by synthetically generated amplitude values constituting edges which are within bandwidth limitations predetermined for the encoded data bits.
Before inserting the data into the digital picture signal, their edges or the edges of the data bits are replaced by synthetically generated amplitude values. Thus, instead of the original edges of the data bits, amplitude values which form a new edge are used. The amplitude values forming the new edges are implemented in such a way that they are within predetermined clock rasters and bandwidth limitations.
Dependent on the data format, data rate, data clock and predetermined bandwidth limitations, the amplitude values may be implemented in such a way that they comply with these conditions.
In this way, different data with different conditions can be inserted into the digital picture signal. This provides an individual adaptation to the predetermined bandwidth limitations and to the data to be inserted.
In one embodiment of the method according to the invention, the edges of the data bits are replaced by amplitude values which constitute at least parts of a sine oscillation, and the edges built up from the amplitude values are inserted into a predeterminable, constant clock raster.
The new amplitude values to be inserted, which replace at least parts of the edges of the original data bits, may advantageously form a sine oscillation which is optimal for a predetermined rise time and hence predetermined bandwidth limitation. To insert these new edges into the desired clock raster, the amplitudes are read in a predeterminable, constant clock raster, for example, from a memory and inserted into the data signal in such a way that they replace parts, particularly edges, of the original data signal. This results in a safe compliance with the bandwidth limitations as well as with a possibly predetermined clock raster.
In accordance with a further embodiment of the invention, the overall data signal is replaced by synthetically generated amplitude values.
Advantageously, the complete data signal, i.e., all bits of the data signal, can be replaced by synthetically generated amplitude values. It is thereby achieved that not only the edges but also the complete data signal inserted into the digital picture signal complies with the conditions relating to bandwidth limitations, but also with standard levels, etc.
As a result, the complete original data signal is replaced by a new signal which consists of the amplitude values which form the edges, and possibly also the other ranges of the signal to be inserted.
For a digital data encoder for encoding data of arbitrary data rates of at least one data signal for jointly transmitting the encoded data with a digital picture signal, the above-mentioned object is achieved, in accordance with the invention, in that a discrete time oscillator is provided, in dependence upon whose output signal synthetically generated amplitude values stored in a memory are accessed in such a way that at least parts of the edges of data bits of the data signal are replaced by synthetically generated amplitude values which constitute edges which are within bandwidth limitations predetermined for the encoded data bits.
The bits of the original data signal (or data signals) are at least partly replaced by amplitude values which are stored in a memory and have previously been generated synthetically. At least parts of the edges of the original data bits are replaced by the amplitude values. The new amplitude values form edges which are within the bandwidth limitations possibly predetermined for the inserted data bits, and comply with further prescriptions which may also be valid for the data signal after its conversion into analog values.
The amplitude values which are inserted into the digital data signal are read in dependence upon the output signal of a discrete time oscillator. With each system clock, such a discrete time oscillator adds the new increment data to the previously formed sum. Thus, with each system clock, the sum generated in the discrete time oscillator and being available as an output signal at the output is increased (or decreased) by the increment applied to the input. The change of the output values of the discrete time oscillator depends on the system clock and on the increment applied to its input. It thereby enables such a discrete time oscillator to make a signal available at the output, whose data values predetermine a clock which is not in an integral ratio with the system clock with which the discrete time oscillator is clocked. This property of the discrete time oscillator is particularly advantageous for the digital data encoder because in this way, the clock raster, with which the amplitude values are formed, is independent of the system clock, or need not be in an integral ratio with this clock.
By changing the increment which is applied to the input of the discrete time oscillator, this clock raster, which is comprised in the values of the output signal of the discrete time oscillator, can be adapted to individual requirements. For example, the increment can be changed for different bandwidth limitations of different data of different data signals so that the digital data encoder according to the invention is capable of supplying different data from different data signals with differently formed or differently steep edges as newly encoded data signals at the output.
Since, as explained above, the discrete time oscillator adds the increment applied thereto upon each system clock to the previously formed sum, its value is constantly increased, so that, dependent on the word length, there will be an overflow at a given moment. With small deviations determined by the overflow rest, this overflow marks those instants at which a rising or falling edge is introduced, within the desired clock raster, into the data signal by inserting the stored amplitude values. The magnitude of the increment value applied to the
Gutsmann Rolf-Dieter
Hackmann Hartmut
Rennert Jens
Gross Russell
Kostak Victor R.
U.S. Philips Corporation
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