US 4,363,009 A · L-C Filter with impedance transformers

Abstract

Input signals having a particular impedance in a particular frequency range are provided. A first transformer has at its input a particular impedance in the particular frequency range and provides a change at its output to a second impedance in the particular frequency range. A filter is constructed to receive the signals from the first transformer and is provided with the second impedance in the particular frequency range. When the second impedance is lower than the particular impedance, the operation of the filter at the second impedance is advantageous because the size of the inductances in the filter is significantly reduced without impairing the quality of the inductances or increasing energy losses in the inductances. A second transformer is constructed to receive the signals from the filter. The second transformer provides the second impedance at its input and provides at its output a change to the particular impedance in the particular frequency range. Means are connected to the second transformer for providing output signals having the particular impedance in the particular frequency range.

Claims16

Dependent claims

In combination for use in a particular range of frequencies between 3 megahertz and 300 megahertz to minimize size,

a filter having input and output terminals and having an impedance of a particular value at the input and output terminals in the particular range of frequencies and including a plurality of inductances and capacitances connected to provide a passage of signals in the particular range of frequencies,
a first transformer connected to the input terminal of the filter and providing, in the particular range of frequencies, a particular change in impedance to the particular value from a particular input value above the particular value, and
a second transformer connected to the output terminal of the filter and providing an impedance change, inverse to the particular change, in the particular range of frequencies from the particular value to the input value of the first transformer.

In combination for use in a particular range of frequencies between 3 megahertz and 300 megahertz,

means for providing input signals having a particular impedance in the particular frequency range,
a first transformer having in the particular frequency range a particular input impedance corresponding to the particular impedance and providing a change to a second impedance lower than the particular input impedance in the particular frequency range,
a filter constructed to receive the signals from the first transformer and having the second impedance in the particular frequency range and constructed to pass signals only in the particular frequency range,
a second transformer constructed to recieve the signals from the filter and to provide an input impedance in the particular frequency range corresponding to the second impedance and to provide a change to the particular impedance in the particular frequency range, and
means connected to the second transformer for providing output signals having the particular impedance in the particular frequency range.

2 more elements

Dependencies are inferred from the claim text.

L-C Filter with impedance transformers

Life of this patent

L-C Filter with impedance transformers

Life of this patent

Abstract

Claims16