A signal processor for effecting the conversion of an audio data signal from one format to another. The present invention also provides the wiring board for electrical tests so fabricated. The two free lateral edge zones are folded back in the direction of the rear face of support band to form one respective accommodating space, while being interconnected, such that a tubular member is formed at least by parts is formed at least by parts of the cover band. The configuration of the stent pattern of the portal region prevents the occurrence of portal overlap of immediately adjacent rings into the portal region during stent deployment.