| 摘要 |
1. Method and circuit for automatic fine frequency tuning with high precision. 2.1 Known analog automatic frequency fine-tuning systems are imprecise and, for example due to a required oscillating circuit, not totally integrable. Known digital automatic frequency fine-tuning systems may offer high precision, but require a comparatively large chip surface and increased power consumption. 2.2 For the purposes of high-precision fine frequency tuning, e.g. to a specific television channel, an adjustable-frequency analog circuit, e.g. an FM demodulator, is adjusted in an integrated circuit with the aid of a control current. The control current generated in a control loop is dependent on a precision corresponding to a reference frequency and on a reference capacity integrated in the chip. Following a frequency selection, the analog circuit is calibrated and the frequency is then fine-tuned in a measurement mode. The analog circuit then operates in normal mode. 2.3 Analog circuit for automatic fine frequency tuning with high precision. <IMAGE> |
