| 摘要 |
A novel filter circuit with variable transfer function, has a signal (UE) input (11) and signal (UA) output (10). The voltage to current converter (1) has first and second outputs (3,2) delivering similar signals, coupled (9) to the output from the filter (10). Of these outputs (3,2), the first (3) is connected via a pure resistance (6), and the second (2) via a capacitance (4), to a reference potential. In addition, an inverting coupler (5) in the filter input (11) circuit, feeds back the second output (2) signal of the converter (1) to its own input (7). The converter (1) is controlled by an input (8), to which the control signal (US) is applied. The voltage to current converter (1) is a transconductance amplifier, e.g. an operational transconductance amplifier (OTA), its amplification controlled by the control signal (US). Its (1) outputs (2,3) are controlled by output stages, each under the control of the same output signal. The control signal (US) is generated in the controller (8), in which the input signal (UE) is evaluated in respect of amplitude and time. The control device (8) receives the input signal (UE). In addition, it also receives signals from at least one of the outputs (2,3) of the converter.
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