| 摘要 |
<p>In a microwave digital radio transmission system receiver in which a modulated carrier wave is converted to an I.F. signal (1) which is demodulated (11-17) to produce phase quadrature signals (I, Q), an apparent frequency error of the carrier wave is detected from the phase quadrature signals (I, Q) and used to control an I.F. amplitude equalizer (2), for compensating for amplitude slope of the I.F. signal. A control signal is produced by low pass filtering (25) a product (22 or 23) of one phase quadrature signal (I or Q) with the time differential (20 or 21) of the other, or the difference (24) between the products of each phase quadrature signal with the time differential of the respective other phase quadrature signal.</p> |
