A first input terminal is connected to a point of connection of a drain terminal of a first transistor and a gate terminal of a fourth transistor. A second input terminal is connected to a point of connection of a drain terminal of a third transistor and a gate terminal of a second transistor. One of first through fourth output terminals to is connected to a source terminal of each of the first through fourth transistors to. A gate terminal of the first transistor and a drain terminal of the second transistor are connected, and a gate terminal of the third transistor and a drain terminal of the fourth transistor are connected.

An aspect includes a filtering method including operating a first filter to filter a first input signal to generate a first output signal; operating a second filter to filter a second input signal to generate a second output signal; and selectively coupling at least a portion of the second filter with the first filter to filter a third input signal to generate a third output signal. Another aspect includes a filtering method including operating switching devices to configure a filter with a first set of pole(s); filtering a first input signal to generate a first output signal with the filter configured with the first set of pole(s); operating the switching devices to configure the filter with a second set of poles; and filtering a second input signal to generate a second output signal with the filter configured with the second set of poles.

A first input terminal is connected to a point of connection of a drain terminal of a first transistor and a gate terminal of a fourth transistor. A second input terminal is connected to a point of connection of a drain terminal of a third transistor and a gate terminal of a second transistor. One of first through fourth output terminals to is connected to a source terminal of each of the first through fourth transistors to. A gate terminal of the first transistor and a drain terminal of the second transistor are connected, and a gate terminal of the third transistor and a drain terminal of the fourth transistor are connected.

The object is to simplify the configuration of a filter in a reception apparatus. The reception apparatus includes a filter. The filter provided in the reception apparatus selects a signal transmission characteristic that is one of a band stop characteristic or a low pass characteristic. Further, selection of the signal transmission characteristic in the filter provided in the reception apparatus is performed in response to a desired signal and an interference signal. In the filter provided in the reception apparatus, passage of the desired signal and attenuation of the interference signal based on the selected signal transmission characteristic are executed.

Polyphase gm-C filters can use matching gm cell components for improved higher image rejection results. Polyphase gm-C filter cells all can be matched by incorporating a matching gmu value in each of the g.sub.m components. The matching gmu value used to replace different gm values can be determined for incorporation into each gm cell component of a filter by: calculating coupling of gmi, gmij by gmi=Ci0 and gmij=Czij0 for i,j; calculating K.sub.i=gmi/gmu; rounding K.sub.i to an integer number, Ni=round(Ki), KiNi and Nij=round(Kij), KijNij; calculating a scaling factor for circuit capacitors C.sub.i and Czijby i=(NiKi)/Ki and ij=(NijKij)/Kij; and adjusting circuit capacitors C.sub.i and Czij by CiCi*(1+i) and CzijCzij*(1+ij). Once the process is completed for i,j, the result can be implemented to match gm cell components of traditional and newly designed polyphase gm-C filters with the matching gmu value.

A filter circuit may include a first path having a first complex baseband filter. The circuit may further include a second path having a second complex baseband filter. The circuit may further include a combiner coupled to an output of the first complex baseband filter and an output of the second complex baseband filter.

A circuit for digital filtering an analog signal converted to digital, including an analog circuit to generate an analog signal, the analog signal including phase and/or gain errors. An analog-to-digital converter (ADC) to convert the analog signal to a digital signal output to a digital signal path. A frequency-dependent corrector filter included in the digital signal path, and configured as a parameterized filter, the parameterized filter configurable based on the DSA control signal with at least one complex filter parameter for each DSA attenuation step, to correct frequency-dependent errors in phase and/or gain.

An aspect includes a filtering method including operating a first filter to filter a first input signal to generate a first output signal; operating a second filter to filter a second input signal to generate a second output signal; and selectively coupling at least a portion of the second filter with the first filter to filter a third input signal to generate a third output signal. Another aspect includes a filtering method including operating switching devices to configure a filter with a first set of pole(s); filtering a first input signal to generate a first output signal with the filter configured with the first set of pole(s); operating the switching devices to configure the filter with a second set of poles; and filtering a second input signal to generate a second output signal with the filter configured with the second set of poles.

Certain aspects of the present disclosure relate to multi-band filter architectures and methods for filtering signals using the multi-band filter architectures. One example multi-band filter generally includes a transconductance-capacitance (gm-C) filter and a reconfigurable load impedance coupled to an output of the gm-C filter, the reconfigurable load impedance comprising a first gyrator circuit coupled to a second gyrator circuit.

The object is to simplify the configuration of a filter in a reception apparatus. The reception apparatus includes a filter. The filter provided in the reception apparatus selects a signal transmission characteristic that is one of a band stop characteristic or a low pass characteristic. Further, selection of the signal transmission characteristic in the filter provided in the reception apparatus is performed in response to a desired signal and an interference signal. In the filter provided in the reception apparatus, passage of the desired signal and attenuation of the interference signal based on the selected signal transmission characteristic are executed.