| 摘要 |
A frequency mixing system provides an expanded dynamic range when compared to the dynamic range(s) of an individual mixer(s) that make up the arrangement. The frequency mixing system uses a feed-forward arrangement to reduce the distortion emanating from a single mixer due to a signal power level which would result in a frequency converted signal outside the dynamic range of the mixer. For example, the frequency mixing system splits an input signal onto a first path and a second path. On the first path, a first mixer frequency mixes the signal to produce a frequency converted signal with distortion, such as intermodulation distortion. On the second path, the amplitude of the signal is attenuated then frequency mixed by a second mixer to produce a frequency converted signal with a low and/or insignificant level of distortion. The first mixer element produces a frequency converted signal with distortion because the signal on the first path enters the first mixer at a power level resulting in a frequency converted signal outside the dynamic range of the first mixer. As such, the higher power level of the signal into the first mixer creates distortion that emanates from the first mixer along with the frequency converted signal. Since the attenuated signal on the second path enters the second mixer at a lower power level resulting in a frequency converted signal within the dynamic range of the second mixer, the second mixer produces the frequency converted signal with the low and/or insignificant level of distortion. After the signals on the first and second paths are frequency converted, the frequency converted signal and distortion are coupled from the first path and combined with the frequency converted signal on the second path, producing the distortion as the prominent signal on the second path. The distortion on the second path is then combined with the frequency converted signal and distortion on the first path to cancel the distortion on the first path and produce the desired frequency converted signal with reduced distortion as compared to the distortion produced if the original input signal would be frequency converted using only the first mixer.
|
