A controllable analog filter, comprising: a secondary signal loop comprising a secondary main path and a secondary feedback path connected between a signal input and a signal output, the secondary signal loop comprising a plurality of primary signal loops in the secondary main path and a secondary adjustable scaling block in the secondary feedback path; each of the plurality of primary signal loops comprising a primary main path, a primary feedback path (110, 510), and a plurality of circuit elements connected in series in each of the plurality of primary signal loops, the plurality of circuit elements comprising: a frequency tunable resonator (502, 1401) connected either in the primary main path or in the primary feedback path; and a primary adjustable scaling block (504, 802, 2704) connected either in the primary feedback path or in the primary main path, respectively, and configured to apply a gain factor, the gain factor being adjustable in a range that comprises a positive gain and a negative gain; and a controller connected to tune each frequency tunable resonator and to adjust the gain factor of each of the primary adjustable scaling blocks and the secondary adjustable scaling block between a negative gain factor and a positive gain factor toward a desired frequency response of the controllable analog filter. a secondary signal loop comprising a secondary main path and a secondary feedback path connected between a signal input and a signal output, the secondary signal loop comprising a plurality of primary signal loops in the secondary main path and a secondary adjustable scaling block in the secondary feedback path; each of the plurality of primary signal loops comprising a primary main path, a primary feedback path (110, 510), and a plurality of circuit elements connected in series in each of the plurality of primary signal loops, the plurality of circuit elements comprising: a frequency tunable resonator (502, 1401) connected either in the primary main path or in the primary feedback path; and a primary adjustable scaling block (504, 802, 2704) connected either in the primary feedback path or in the primary main path, respectively, and configured to apply a gain factor, the gain factor being adjustable in a range that comprises a positive gain and a negative gain; and a controller connected to tune each frequency tunable resonator and to adjust the gain factor of each of the primary adjustable scaling blocks and the secondary adjustable scaling block between a negative gain factor and a positive gain factor toward a desired frequency response of the controllable analog filter. a frequency tunable resonator (502, 1401) connected either in the primary main path or in the primary feedback path; and a primary adjustable scaling block (504, 802, 2704) connected either in the primary feedback path or in the primary main path, respectively, and configured to apply a gain factor, the gain factor being adjustable in a range that comprises a positive gain and a negative gain; and a controller connected to tune each frequency tunable resonator and to adjust the gain factor of each of the primary adjustable scaling blocks and the secondary adjustable scaling block between a negative gain factor and a positive gain factor toward a desired frequency response of the controllable analog filter.