FI114522B - A method for processing a serial digital data signal - Google Patents

Abstract

In order to obtain reliable information more rapidly when decoding signal elements of a serial, digital data signal in a television signal, the signal element is scanned at a scanning frequency which corresponds to a common multiple of the frequency positions of the signal elements, if the signal element only bears a single information unit. The sequence of the scan values produced when a signal element is scanned is subject to a majority check.

Description

114522

A method for processing a serial digital data signal - För-farande for behandling av en digital data signal i serieform

The invention relates to a method according to the preamble of claim 1. Such a method is known from DE-41 12 712 A1.

5 When transmitting various aspect ratios and additional information (e.g., various signal pre-filtering) for widescreen receivers, DE-41 12 712 A1 discloses transmitting serial digital signals in the first half of a television signal line 23. These serial digital signals have a special composite character: for the whole image (= half-line 10 23), during the initial phase, they consist, for example, of signal elements at different frequencies, and 14 bi-phase modulated signal elements, of which four signal elements error protection element and indicate aspect ratio; and the other 10 signal elements indicate other additional information. The decoding of this composite structure is not usually a frequency difference, so that the signal elements can be separately decoded. Because aspect ratio is very crucial information, it is necessary to wait and evaluate the data of at least three consecutive full images before making a final decision - in order to achieve a minimum transmission rating - *: · ': also under unfavorable reception conditions, especially YLE; 20 on the edges of the area. User-initiated “zapping”. ·. however, this relatively slow decision-making results in a widescreen: wrong aspect ratio choices.

:,:. Accordingly, it is an object of the invention to provide a sig-; when decoding the elemental elements, provide a fast and reliable decision.

This object is solved according to the invention by the features of claim 1.

; Preferred embodiments and variations of the method of the invention are apparent from the dependent claims.

.: The invention proceeds from the idea of avoiding dividing the received digital signal _ · 30 into higher and lower frequency signal elements in terms of frequency:. ·. and the transponder is provided with a sampling frequency common to all signal elements, corresponding to a common multiple of the frequencies present in the signal elements. Thus, the signal elements are sampled at a substantially higher sampling rate than the "oversampling" required by the sampling theorem, whereby a single sample value is no longer available for the entire image and for each signal element, but rather a series of multiple sample values. This array of sample values available for each signal element and for the entire image allows for a statistical majority of 5, which allows a more reliable decision to be made without having to take into account subsequent pictures. The end result is that the aspect ratio announcement can be decided on the basis of a single image, so that even with fast handoffs by the user, the correct aspect ratio of the widescreen receiver is always guaranteed.

The invention will now be explained in more detail with reference to the drawings. In the drawings: Figure 1 shows an arrangement for carrying out the method according to the invention; and Figure 2 is a diagram of signals occurring at different points in the arrangement of Figure 1.

The arrangement shown in Fig. 1 is supplied with a serial digital data signal according to Fig. 2a, which is transmitted in time multiplexed with an analog television 15 signal in the first half of the television line 23. In the case of a data signal, this is a so-called "Wide-Screen-Signaling" signal, which in the initial stage has several signal elements 2, 3, and 14 at the same frequency; 2a is only a part. . each image of the transmitted data signal on the 23rd half of the television line.

:, '.' The input digital data signal of Figure 2a is separated and limited in step 11 from the television signal as shown in Figure 2b. In the next step 21:; whereas the extracted and limited data signals are sampled at a sampling rate,. ·. which is the multiple of the frequencies of the signal elements at different frequencies.

For the signal element 4 of Figure 2a, this relatively high-frequency sampling 25 means that each of the signal elements 4 will receive a plurality of, in the example shown, six samples, as shown in Figure 2c.

Since each signal element 4 of length P (Figure 2c) is bi-phase modulated, the sampling value of the inverted portion of each signal element in step 31 is inverted, as in Figure 2d. has been presented. After the subsequent demodulation in step 31, an additional ''; · 'Separating the sample values of the signal elements 4 whose logical states are summed; * 'in the next step 41 - for each signal element 4 separately. Seu- •: ·. in the final step 51, the result of the summation is examined - again for each signal element 4 separately, with a majority analysis in a simple or 3114522 weighted form, taking into account a given threshold. For example, a sum result is considered correct if 70% of the summed sample values of a given signal element 4 corresponds to a logical state. If the summing results of all low-frequency signal elements 4 per image exceeds the threshold, then the total product 5 is kept secure and is further passed to step 61. In step 61, a 3-bit word consisting of three low frequency signal elements is decoded.

Claims (3)

A method for processing a serial digital data signal which is part of a TV signal and is separated from it, which is further inserted into an unchanging data frame and which has signal elements in different frequency states at which the data signal is detected and the data signal is detected. The detected detection values are correlated with the data frame of the detected data signal, characterized in that, in the case that each signal element carries only a single information unit, the signal element is detected with a relatively high frequency position, its detection frequency, the detection frequency being equal to a multiplicity and frequency positions of the signal elements, and of the consequence of the detection values occurring in the detection of the signal element undergo a majority test in simple or weighted form. Method according to claim 1, characterized in that the signal element is biphasically encoded, that before the majority test in simple or weighted form the detection values for the inverted sections of the signal element are inverted and that the uninverted and inverted detection values are evaluated as valid when the number of detection values of the signal element is inverted. one of the polarity is above a predetermined threshold. Method according to claim 1 or 2, characterized in that as a digital data signal, a signaling signal is used for the current picture format of a wide-screen receiver and in the event that the data signal is reproduced by a home video player: only the tested signal element is used for controlling the wide-screen receiver. • image format. I I • tl • (1 · »