1. A filtering device for use in a phase locked loop controller of a signal generator, the controller having a first loop and a second loop, the first loop having a first loop bandwidth and a first correction signal, the second loop having a second loop bandwidth and a second correction signal, the filtering device comprising: a first filtering apparatus including a first time constant, a first port, a second port, and a third port, the first port coupled to the first correction signal, the second port coupled to a control input of the signal generator; and a second filtering apparatus including a second time constant and a first port, the first port coupled to the third port of the first filtering apparatus and the second correction signal, wherein the first loop bandwidth is dependent upon the first time constant and the second time constant, and the second loop bandwidth is dependent upon the second time constant.