Gain tracker for digital modem
Baseband carrier phase corrector
Gain and phase correction in a dual branch receiver
Direct conversion receiver with tri-phase architecture
Digital demodulator for amplitude or angle modulation using truncated nonlinear power series approximations Patent #: 5121072
ApplicationNo. 660492 filed on 02/25/1991
US Classes:375/344, Automatic frequency control375/345, Automatic gain control455/324Homodyne (i.e., zero beat or synchrodyne reception)
ExaminersPrimary: Kuntz, Curtis
Assistant: Ghebretinsae, T.
Attorney, Agent or Firm
International ClassH04L 027/06
AbstractA system for controlling for gain and phase errors due to mismatches between signal channels in direct conversion receiver having a pair of signal channels carrying I and Q baseband component signals which are in quadrature. In accordance with the system new I' and Q' signals are generated which may be viewed as analogs of the I and Q baseband components but which are related to twice the phase angle defined by the original I and Q baseboard components signal components. Phase angles are determined based on the original I and Q baseband components signals and the new I' and Q' signals. An error signal is then formed from these signals which can be analyzed to determine the gain and phase errors affecting the I and Q baseband components. These components can then be adjusted to correct for gain and phase errors in order to compensate for hardware mismatches between the signal channels in the receiver.