Reivindicaciones

1. A device for the certified bandwidth measurement of a broadband network access, characterised in that it comprises processing means (1) for performing a number of measurements of parameters related to the quality of a broadband network a network interface (2) for connecting to the network access to be measured storage means (3) for storing the results of the measurements and a communication port (4) in communication with an external reference clock (6) which is calibrated and legally valid wherein the processing means (1) communicate through the communication port (4) with the external reference clock (6) calibrated, for the assessment of the parameters. 2. Apparatus according to claim 1, characterised in that it comprises pulse counting means (7) for the calibration signals which come from the communication port (4), associated to the processing means (1). 3. Apparatus according to claim 1, characterised in that the processing means (1) are either a CPU or an FPGA. 4. Apparatus for the certified measurement of bandwidth in a network access according to claim 1, characterised in that the processing means (1) performs the measurements listed in the 29<th> March 2006 Spanish ministerial order ITC/912/2006 , published in the Spanish BOE dated 31<st> March 2006. 5. Apparatus according to clam 1, characterised in that the storage means (3) are a Flash memory or a hard disk. 6. Calibration method of an apparatus according to any of the claims 1-5, characterised in that it comprises the following steps: sending a signal (5) through the communication port (4), namely a pulse, exactly when the processor (1) starts the TCP connection (8) to the network (9) that performs the file download (right before sending the SYN packet). turning off (11) the pulse (5) when the FIN packet (10) is sent to indicate the connection end, registering the real measurement or time (A) by the external pulse counter (7) registering the measure or time (B) of the internal clock of the processing means (1), comparing both measurements to assess the deviations that the apparatus may be incurring. 7. A computer program characterised in that it comprises code means to perform the calibration method according to claim 6, when this program is run in a computer. 8. A computer readable media that contains a computer program comprising code means to perform the calibration method according to claim 6, when this program is run in a computer.