HIGHLY SELECTIVE FILTERING DEVICE AND CORRESPONDING FILTERING METHOD

摘要

The invention proposes a filtering device 10 having a frequency response which is symmetrical, using asymmetrical filters 21 and 22 coupled by transposition means 23 and 24. The advantageous characteristics of the asymmetrical filters 21 and 22 are retained and the faults associated with the asymmetry are eliminated. The asymmetrical filters 21 and 22 are, for example, quartz filters. The invention also proposes an external transmission and reception unit 1, using the filtering device 10 with the application of the filtering method.