JOINT DRM AM SIMULCAST ENCODER AND TRANSMITTER EQUALIZER

Abstract

The present invention relates to a signal estimation apparatus, a signal deviation estimation apparatus, a signal pre-transmission preparation apparatus and a simulcast broadcasting system as well as corresponding methods and a corresponding computer program product. In particular, the present invention relates to the above, wherein a predetermined non-linearity, e.g. for modelling a transmission of a broadcast signal, is applied to a signal so as to obtain an estimation signal e.g. of a transmitted broadcast signal.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features of the invention, as well as the invention itself, both as to its structure and its operation will be best understood from the accompanying figures, taken in conjunction with the accompanying description.

FIG. 1 shows the schematic spectrum of a simulcast signal in accordance with the teachings of EP 1 276 257.

FIG. 2 demonstrates a signal flow in a method/apparatus/program product in accordance with a first preferred embodiment of the invention suitable for generating a broadcasting signal.

FIG. 3 demonstrates a signal flow in a method/apparatus/program product in accordance with a second preferred embodiment of the invention suitable for generating a broadcasting signal.

FIG. 4 demonstrates a signal flow in a method/apparatus/program product in accordance with a third preferred embodiment of the invention suitable for generating a broadcasting signal.

Claims

1. Signal estimation apparatus, comprising: first modulation means (1) configured and adapted for modulating a digital input signal to an upper or lower sideband of a predetermined carrier,second modulation means (2) configured and adapted for modulating an analog input signal to the other of said upper or lower sidebands,mixing means (4) configured and adapted for mixing at least said upper and lower sideband signals so as to output a mixed signal,first processing means, including modelling means (7) for applying a predetermined non-linearity, configured and adapted for processing said mixed signal so as to output a processed signal, andan envelope demodulator (9) configured and adapted for demodulating said processed signal based on its envelope so as to output an estimation signal.

2. Signal estimation apparatus according to claim 1, wherein said mixing means is configured and adapted for mixing said predetermined carrier with said upper and lower sideband signals so as to output said mixed signal.

3. Signal estimation apparatus according to any one of the preceding claims 1 or 2, wherein said first processing means includes equalizer means (8).

4. Signal estimation apparatus according to claim 3, wherein said equalizer means comprises an iterative equalizer.

5. Signal deviation estimation apparatus, comprising: a signal estimation apparatus of any of the preceding claims,first delay means (5, 13) configured and adapted for applying a delay to an analog reference signal so as to output a delayed analog reference signal, andsubtracting means (10) configured and adapted for calculating a difference between said estimation signal and said delayed analog reference signal so as to output an estimated deviation signal.

6. Signal deviation estimation apparatus according to claim 5, wherein: said analog reference signal is said analog input signal.

7. Signal pre-transmission preparation apparatus, comprising: a signal deviation estimation apparatus according to any one of the claims 5 or 6,second delay means (5) configured and adapted for applying a delay to said analog input signal so as to output a delayed analog input signal,weighting and summing means (11, 12) configured and adapted for weighting said estimated deviation signal and summing the result with said delayed analog input signal so as to output a correction signal, andthird delay means (6) configured and adapted for applying a delay to said digital input signal so as to output a delayed digital signal.

8. Simulcast broadcasting system, comprising: a signal pre-transmission preparation apparatus according to claim 7,third modulation means (21) configured and adapted for modulating said delayed digital signal to said upper or lower sideband of a predetermined carrier,fourth modulation means (22) configured and adapted for modulating said correction signal to said other of said upper or lower sidebands,second processing means, including mixing means (24) for mixing a signal corresponding to said predetermined carrier with said upper and lower sideband signals, configured and adapted for processing said upper and lower sideband signals so as to output a pre-transmission signal, andtransmitter means (26) configured and adapted for transmitting said pre-transmission signal.

9. Simulcast broadcasting system according to claim 8, comprising: one or more additional signal pre-transmission preparation apparatuses in accordance with claim 7, whereinsaid additional signal pre-transmission preparation apparatuses are connected in series between said signal pre-transmission preparation apparatus and said third and fourth modulation means,each of said additional signal pre-transmission preparation apparatuses receives, as said analog input signal, said correction signal of an immediately preceding signal pre-transmission preparation apparatus in said series connection,each of said additional signal pre-transmission preparation apparatuses receives, as said analog reference signal, said delayed analog reference signal of said immediately preceding signal pre-transmission preparation apparatus, andeach of said signal pre-transmission preparation apparatuses receives, as said digital input signal, said delayed digital signal of said immediately preceding signal pre-transmission preparation apparatus.

10. Simulcast broadcasting system of claim 8, wherein: said signal pre-transmission preparation apparatus constitutes part of an iterative loop configured and adapted to have the effect of one or more additional signal pre-transmission preparation apparatuses connected in series between said signal pre-transmission preparation apparatus and said third and fourth modulation means,each of said additional signal pre-transmission preparation apparatuses receives, as said analog input signal, said correction signal of an immediately preceding signal pre-transmission preparation apparatus in said series connection,each of said additional signal pre-transmission preparation apparatuses receives, as said analog reference signal, said delayed analog reference signal of said immediately preceding signal pre-transmission preparation apparatus, andeach of said signal pre-transmission preparation apparatuses receives, as said digital input signal, said delayed digital signal of said immediately preceding signal pre-transmission preparation apparatus.

11. Simulcast broadcasting system according to any one of the preceding claims 8 to 10, wherein said second processing means comprises equalizer means identical to an equalizer means in one or more first processing means thereof.

12. Method for signal estimation, comprising the steps of: modulating a digital input signal to an upper or lower sideband of a predetermined carrier,modulating an analog input signal to the other of said upper or lower sidebands,mixing at least said upper and lower sideband signals so as to obtain a mixed signal,processing said mixed signal, including applying a predetermined non-linearity, so as to obtain a processed signal, anddemodulating said processed signal based on its envelope so as to obtain an estimation signal.

13. Method for signal estimation according to claim 12, wherein said mixing step comprises mixing said predetermined carrier with said upper and lower sideband signals so as to obtain said mixed signal.

14. Method for signal estimation according to any one of the preceding claims 12 or 13, wherein said processing step includes equalization.

15. Method for signal estimation according to claim 14, wherein said equalization comprises iterative equalization.

16. Method for signal deviation estimation, comprising a method for signal estimation signal estimation according to any one of the preceding claims 12-15 as well as the steps of: applying a delay to an analog reference signal so as to obtain a delayed analog reference signal, andcalculating a difference between said estimation signal and said delayed analog reference signal so as to obtain an estimated deviation signal.

17. Method for signal deviation estimation of claim 16, wherein said analog reference signal is said analog input signal.

18. Method for signal pre-transmission preparation, comprising a method for signal deviation estimation according to any one of the preceding claims 16 or 17 as well as the steps of: applying a delay to said analog input signal so as to obtain a delayed analog input signal,weighting said estimated deviation signal and summing the result with said delayed analog input signal so as to obtain a correction signal, andapplying a delay to said digital input signal so as to obtain a delayed digital signal.

19. Method for signal pre-transmission preparation according to claim 18, comprising one or more re-iterations of the method for signal pre-transmission preparation according to claim 18, wherein: each reiteration of said signal pre-transmission preparation method receives, as said analog input signal, said correction signal of an immediately preceding iteration of said method for signal pre-transmission preparation,each reiteration of said signal pre-transmission preparation method receives, as said analog reference signal, said delayed analog reference signal of said immediately preceding iteration, andeach reiteration of said signal pre-transmission preparation method receives, as said digital input signal, said delayed digital signal of said immediately preceding iteration.

20. Method for simulcast broadcasting, comprising a method for signal pre-transmission preparation according to any one of the preceding claims 18 or 19 as well as the steps of: modulating said delayed digital signal of a last iteration of said method for signal pre-transmission preparation to said upper or lower sideband of a predetermined carrier,modulating said correction signal of said last iteration to said other of said upper or lower sidebands,processing said modulated delayed digital signal and said modulated correction signal, including mixing a signal corresponding to said predetermined carrier with said upper and lower sideband signals, so as to obtain a pre-transmission signal, andtransmitting said pre-transmission signal.

21. Method for simulcast broadcasting of claim 20, wherein said step of processing said modulated delayed digital signal and said modulated correction signal comprises equalization identical to said equalization in said processing of said mixed signal in one or more iterations of said method for signal pre-transmission preparation.

22. Computer program product, comprising computer program means for carrying out the method steps according to any one of the preceding claims 12 to 21 when executed on a computer, digital signal processor or the like.