T 0111/92 27-07-1994

Reasons for the Decision

1. The decision to be taken is whether the admissible appeal (cf. point III) is allowable (Article 110(1) EPC).

For this purpose, it is to be decided whether the Appellant's main request or, otherwise, his auxiliary request is allowable.

The only issue to be dealt with for this decision is, in the present case, whether the subject-matter of the independent claims of these requests involve an inventive step.

2. Main Request

2.1. Claim 1 is, according to its wording (cf. point VIII), understood as defining an audio-reproducing apparatus for signals recorded by a rotary head assembly, in which means are incorporated for producing an echo effect by reproducing one of two signals, recorded on two tracks, with a delay with respect to the other.

Since the reference signs placed between parentheses do not limit the claim (Rule 29(7) EPC), this claim does not in any way define the "types" of signals recorded except that they stem from the same source. Nor does the claim in any way specify the two tracks mentioned.

This means that any envisageable possibility is left open. As examples only, the wording of the claim would neither exclude the general possibility that both signals are, although of a "first" and "second" type, nevertheless similar, nor the more specific possibility of their being left-hand and right-hand stereo signals (such as L and R INPUT in D5, Figs. 1 and 10). Although the Board would agree that these exemplary possibilities might appear to be not very probable in the sense that their usefulness would not be immediately apparent, it is considered that in some cases these, or similar, possibilities may nevertheless be realistic.

This view is confirmed by the very fact that the existence of two (the main and auxiliary) requests with and without features restricting the claim (to PCM and FM signals) can only be interpreted as meaning that the Appellant seeks, in the first place, a broader scope of protection in the sense of an application of echo creating means in any two-track audio-reproducing apparatus, whatever the "first" and "second" types of signals and whatever the kinds of recording.

The reference to a rotary head would, in this context, appear to be insignificant because its use is in no way further specified. It can, in the circumstances, be understood as a, possibly unnecessary, restriction to a (for whatever reason, e.g. higher fidelity and/or additional video) more sophisticated kind of recording.

Seen in this general context, it is not even clear that the feature "means for reproducing ... such that one is reproduced with a delay ..." would be intended to mean anything else than that there are provided, within the said "means for reproducing", specific "means" (such as E in D4, Fig. 1) introducing said delay.

2.2. With Claim 1 so interpreted as defining the general application of the idea, known from any of the citations D2 to D5, of creating an echo effect in a two-track audio-reproducing apparatus, incidentally having a rotary head assembly, must be considered as being obvious to the person skilled in the art.

This is the more so, as D5 directly proposes the application of that idea in any tape deck, phono pickup etc. (column 19, lines 25-26), i.e. in audio-reproducing apparatus of any kind including their possible incorporation in video recorders.

2.3. As follows from the above, reference to D1 is not necessary to conclude obviousness.

On the contrary, D1 would appear to be too specific as a proper starting point for a claim defining the application of the idea of creating an echo effect in audio-reproducing apparatus in general, viz. including those which do not employ the PCM and FM technologies.

2.4. As a further consequence of the general interpretation of Claim 1 allowed by its wording, the Appellant's arguments submitted in favour of an inventive step would appear not to support that claim in its generality.

Those arguments are understood to mean that the skilled person would have had a prejudice against mixing, in the respective context, the processed PCM and FM audio signals. In an application, where the two types of signals mixed do not have fundamentally different properties (cf. in this respect below, point 3.2), according to the above finding (point 2.2), it cannot be concluded that such a prejudice exists.

2.5. The subject-matter of Claim 1 being, for these reasons, obvious from the prior art as represented by D2 to D5, when read with the common general knowledge of the person skilled in the art of reproducing recorded audio signals, it does not involve an inventive step, and that claim cannot therefore be allowed.

2.6. Even though for this reason the Appellant's main request must fail, the Board has considered, and will deal, also with the independent Claim 4.

2.7. Claim 4 in effect claims nothing but the incorporation of the reproducing apparatus of Claim 1 in a recording and reproducing apparatus, the recording part of that apparatus being specified only by the recording being done by said rotary head assembly mentioned already in Claim 1. Otherwise, that apparatus may be of any kind whatsoever.

2.8. The incorporation of an audio-reproducing apparatus in a recording and reproducing apparatus (such as a "tape deck", D5) is, however, a usual technique in this field which does not need to be documented.

For an audio-reproducing apparatus incorporated in a recording and reproducing apparatus, therefore, the above line of argument leading to the conclusion of obviousness applies in fully the same way.

2.9. The subject-matter of Claim 4 does not, therefore, involve an inventive step, and this claim is not allowable.

3. Auxiliary Request

3.1. Following the restriction of Claim A1 to the audio signals being a frequency-modulated and a pulse-code- modulated signal, D1 has to be regarded as the prior art coming nearest to the claimed invention so that it represents the best starting point.

Seen from this starting point, the Appellant's arguments (cf. point IX) submitted in favour of an inventive step are, contrary to the case of the main request (cf. point 2.4), fully to be taken into account.

3.2. In effect, these arguments mean that the skilled person would never consider combining the PCM and FM audio signals for any reason. In other words: he would have a prejudice against such combining.

The Board agrees with this view for the following reasons:

The PCM audio signal is generally, and for factual reasons, regarded as an "expensive" signal. It is, as a digitally-processed signal, of high quality in that it will, normally, have both hi-fi properties (large audio bandwidth and flat frequency response) and high signal- to-noise ratio. The FM audio signal being specifically designed for "cheaper" applications, it is (even if it is "better" than an AM signal would be) to be regarded as a signal of low quality as far as both frequency response and noise are concerned. It would appear to go against all the tendencies on which the introduction of pulse-code-modulation in audio technology are based, if such a hi-fi signal is mixed with a low-quality audio signal such as the FM signal of D1.

In addition, the PCM audio signal will normally, in practical applications, be a stereo, i.e. two-channel, signal whereas the FM audio signal will normally be of the simple mono kind. Without a good reason, the skilled person would not combine signals of so fundamentally different properties.

Moreover, as submitted by the Appellant, even if the PCM and FM audio signal may both be available, this would only be for reasons of chip manufacturing; therefore, the skilled "user" would not even be aware that they could be used together.

It is, in addition, not even certain that he would be aware, considering the natural delay between the processed PCM and FM audio signals which are normally (e.g. for synchronisation with the picture in a video application) disregarded, of the fact that said delay would be of the order allowing an echo effect to be produced.

3.3. The Board would maintain the view that an application of the idea of creating an echo effect by applying measures such as those proposed in D2 to D5 to an audio- reproducing apparatus known from D1 would be obvious.

However, because of the aforementioned prejudice, the skilled person would not implement this idea by mixing the PCM audio signal with the FM audio signal having such fundamentally different properties, e.g. qualities. The more so, as he might not be aware of their being available at the same time and of their relative delay being of the required order.

Instead, he would implement the said idea in the conventional way disclosed in D2 to D5, i.e. by providing delay means specifically designed for this purpose, and by mixing the undelayed audio signal with a thus delayed replica of the same audio signal. Particularly in the case of the PCM audio signal, which is "expensive" anyway, he would not be deterred from doing this by the necessity of adding to the electronics a delay means which would not contribute much to the overall costs of the apparatus.

3.4. Claim A1 is therefore considered to be allowable.

3.5. The same necessarily applies to Claim A4, this claim defining the same audio-reproducing apparatus as incorporated in an audio, and video, recording and reproducing apparatus; cf. also point 2.7.

3.6. The independent claims of the auxiliary request are, therefore, considered to be allowable.

4. Conclusions

4.1. Whereas the Appellant's main request is to be refused (cf. points 2.6 and 2.9), the auxiliary request, as far as the independent claims are concerned, and, consequently, the request that the decision under appeal be set aside, are allowed.

4.2. In the circumstances of the present case, where the dependent claims, numerous as they are, have neither been adapted for the purposes of the auxiliary request nor examined under Rule 29(3) ff. EPC, and where the description has been amended but not so as to be in accordance with the claims of the auxiliary request, the Board making use of the discretion given to it by Article 111(1), second sentence, EPC, finds it appropriate to remit the case, for the purposes mentioned, to the department of first instance for further prosecution, reference being made to Article 111(2), first sentence, EPC.