Attenuators are used to damp a signal. Using pure ohmic resistors the circuit can be realized for a very high bandwidth, i.e. from DC to many GHz. The power attenuation is defined as:

where and are the input and output power and and are the input and output voltages.

Fig. 14.1 shows an attenuator using the -topology. The conductances can be calculated as follows.

(14.2) | ||

(14.3) | ||

(14.4) |

where and are the input and output reference impedances, respectively. The -attenuator can be used for an impedance ratio of:

(14.5) |

Fig. 14.2 shows an attenuator using the T-topology. The resistances can be calculated as follows.

(14.6) | ||

(14.7) | ||

(14.8) | ||

(14.9) |

where is the attenuation ( ) according to equation 14.1 and and are the input and output reference impedance, respectively. The T-attenuator can be used for an impedance ratio of:

(14.10) |

This document was generated by