首页>
外国专利>
An integrated RC bandpass filter with automatic centre frequency calibration
An integrated RC bandpass filter with automatic centre frequency calibration
展开▼
机译：具有自动中心频率校准功能的集成式RC带通滤波器
展开▼
页面导航
摘要
著录项
相似文献
摘要
An integrated bandpass filter comprises a loop of LP, HP and amplifier sections. Filter Q is adjusted by the multiplier 36. Multipliers 35 and 37 allow adjustment of the time constant of the LP and HP sections so that the filter's centre frequency may be controlled to compensate drift and manufacturing variations in the integrated resistors and capacitors. The filter resistors may be on one IC and the filter capacitors on another IC. A calibration circuit (figure 11) provides an output proportional to the time constant of a dummy RC circuit. This output controls the multipliers in the filter. The multipliers may use logarithmic techniques. Interaction between the sections is reduced by interstage buffers or by use of internal stage feedback to reduce output impedance.
展开▼
