Method for estimating a signal-to-noise ratio

1. A method for estimating a signal-to-noise ratio of a received digital radio signal, the estimating method comprising:

a detecting step consisting in recovering a received synchronization symbol contained in the received digital radio signal; and

an estimating step configured to determine the signal-to-noise ratio of the received digital radio signal, depending on the difference between a first received synchronization signal and a second received synchronization signal, the first and second received synchronization signals being comprised in the received synchronization symbol.

2. The estimating method as claimed in claim 1 , wherein said signal-to-noise ratio is a ratio between, on the one hand, two times a value of the second received synchronization signal and, on the other hand, the difference between the first and second received synchronization signals.

3. The estimating method as claimed in claim 2 , wherein the received digital radio signal corresponds to a modulated digital radio signal comprising an initial synchronization symbol, the initial synchronization symbol comprising a first synchronization signal and a second synchronization signal, said first and second synchronization signals being identical.

4. The estimating method as claimed in claim 3 , wherein the first received synchronization signal comprises the first synchronization signal and a first noise signal, and the second received synchronization signal comprises the second synchronization signal and a second noise signal, the estimating step being carried out depending on the similarity between the first synchronization signal and the second synchronization signal of the initial synchronization symbol, and on the inconsistency between the first noise signal and the second noise signal.

5. The estimating method as claimed in claim 1 , wherein the received digital radio signal comprises a plurality of successive symbols the first symbol of which is said received synchronization symbol, said received synchronization symbol being a beacon symbol defined in accordance with the CDR standard, CDR being the acronym of convergent digital radio.

6. A method for estimating a first signal-to-noise ratio of a received analog radio signal after transmission, comprising:

transmitting the received analog radio signal in a frequency band in which a digital radio signal is also transmitted; and

determining said first signal-to-noise ratio depending on a second signal-to-noise ratio of said received digital radio signal, the second signal-to-noise ratio being computed by the estimating method as claimed in claim 1 .

7. The estimating method as claimed in claim 6 , wherein the first signal-to-noise ratio is computed by multiplying the second signal-to-noise ratio by a correlation coefficient.

8. The estimating method as claimed in claim 7 , wherein the correlation coefficient is determined depending on a spectrum mode chosen for the transmission of the analog radio signal and of the digital analog radio signal.

9. The estimating method as claimed in claim 8 , wherein the correlation coefficient is equal to 0.701.

10. A radio receiver configured to estimate a signal-to-noise ratio of a received analog radio signal, comprising a module configured to implement the estimating method as claimed in claim 6 .

11. A radio receiver configured to estimate a signal-to-noise ratio of a received digital radio signal, comprising a module configured to implement the estimating method as claimed in claim 1 .