Multistandard transceivers: state of the art and a new versatile implementation for fully active frequency agile filters
The various architectures of transceivers for current standards are firstly compared. Different possibilities to achieve multi-standard transceivers are also recalled and compared. We demonstrate that ease of realization and flexibility evolve in opposite directions. The advantages and drawbacks of reconfigurable active filters are indicated. We demonstrate that the second generation current controlled conveyor operating in current mode is perfectly suitable for the realization of frequency-agile filters. After a brief recall of the essential points of agile filters, a second order frequency agile bandpass filter operating in current mode is implemented with CCCII+. It has four central frequencies whose values could be selected digitally. The validation results show that its tuning ratio n = f(0max)/f(0min) is equal to 5.1 with f(0max) = 1.22 GHz.
multistandard transceivers frequency agile filters current mode