This paper presents a BiCMOS realization of a structure-programmable continuous-time filter built with sections synthesized by the image-parameter method and demonstrating the feasibility of the voltage companding technique. The circuit implements any one of four lowpass filters of order 2-5 or one fourth-order bandpass filter by interconnecting a set of identical cells. The filter is obtained by a component level substitution transforming a g/sub m/-C structure into its log-domain equivalent. The g/sub m/-C structures are derived from LC ladder prototypes which are synthesized using the image-parameter method. This technique can be extended to realize higher order filters using multichip configurations. As an example, six lowpass filters (order 6-11) and three bandpass filters (order 6, 8, and 10) have been measured using three chips. The programmable filters can additionally be frequency tuned from 10-100 kHz with a low total harmonic distortion (THD) despite their class AB operation.
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机译：本文提出了BiCMOS的结构可编程连续时间滤波器的实现，该滤波器由通过图像参数方法合成的部分构建而成，并证明了电压压扩技术的可行性。该电路通过互连一组相同的单元来实现2-5阶的四个低通滤波器或一个四阶带通滤波器中的任何一个。该滤波器是通过将g / sub m / -C结构转换为对数域等效项的组件级替换获得的。 g / sub m / -C结构源自使用图像参数方法合成的LC梯形图原型。该技术可以扩展为使用多芯片配置实现更高阶的滤波器。例如，使用三个芯片测量了六个低通滤波器（6-11级）和三个带通滤波器（6、8和10级）。尽管可编程滤波器具有AB类功能，但它还可以在10-100 kHz的频率范围内以较低的总谐波失真（THD）进行频率调谐。
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