Digital conversion of TDM into frequency multiplex signals - using low pass and high pass filters for different signals for obtaining desired channels

摘要

In the conversion system the frequency multiplex signal consists of stagewise groups. Every two signals form a group signal with doubled channel number. One signal is used to form a sweep position, while both signals double the scanning frequency. Then the process signals are combined by two filters, or by a complementary filter. One signal is passed through a low pass filter, the other through a high pass filter. For a specified channel number each stage of the entire arrangement is formed by an identical elemental structure. If three signals are used the scanning frequency is tripled. Pref. the first two signals are combined by passing through filters, and the combined signal is then combined inthe same manner with the third signal. Alternately, only the third signal is filtered and added to the combined signal by a summation element. Typically, digital wave filters are used as complementary filters.