![]() ![]() ![]() This copy is referred to as an image and has a reduced amplitude compared to the desired signal. Imperfect cancellation results in an inverted copy of the desired signal appearing on the opposite side of the local oscillator (LO) frequency from the desired signal when transmitting. This is described in the article referenced above. Any mismatch of phase or amplitude of those signals degrades the summing and cancellation that occurs when the upconverted I and Q signals are combined. A complex mixer has in-phase (I) and quadrature-phase (Q) signals. While providing many advantages due to such high integration, ZIF radios bring challenges as well. Block diagram of the RadioVerse AD9371 transceiver. For an excellent starting point to understanding the complex mixers used in ZIF transceivers, refer to the article on complex RF mixers referenced at the end of this article. As shown in the block diagram of the AD9371 in Figure 1, both the main receive and transmit signal paths use one complex mixer stage to translate between the radio frequency (RF), which is centered around the local oscillator (LO) frequency, and baseband, which is centered around dc. ![]() Image Rejection Basicsīoth the AD9361 and AD9371 families use zero intermediate frequency (aka, zero-IF or ZIF) architectures, which results in a very high level of integration and significantly reduces the number of frequency-dependent components in the system. Armed with that information, customers can make informed decisions and select the right transceiver for the application. This article explores where images come from, what they are, and how they impact overall system performance. Image rejection is one of the areas of performance that differs between the two families. The two families have significantly different levels of performance in several key areas and power consumption is also quite different between the two product families. The AD9361 and AD9371 RadioVerse ™ wideband transceiver families both offer an unparalleled level of integration, as well as a plethora of features and many user-selectable options. Mirror, Mirror on the Wall-Understanding Image Rejection and Its Impact on Desired Signals ![]()
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