| 摘要 |
This invention describes a system and a method to generate a modulated signal of an arbitrary angle and magnitude using two equal constant-amplitude carrier waves, each with adjustable-phase angles. The modulated signal is vector sum is created by combining the first carrier wave with the second carrier wave, where the phase angles of the first and second carrier waves determines both the magnitude and the phase of the desired modulated signal The necessary phase angle adjustment of the first and the second carrier waves can be achieved by rapidly reprogramming numerically controlled oscillators (NCOs), which are also known as direct digital synthesis (DDS) signal generators. This technique eliminates the inefficiency of conventional linear amplifiers and allows a single transmitter to efficiently generate signals with multiple modulation types. This technique also eliminates conventional modulators, which convert baseband signals into radio frequency signals. The generated signal may be transmitted, or utilized locally in test equipment, or for driving devices such as lasers, or for recording.
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