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You can change the cookie settings in your browser. Submitting the report failed. Please, try again. If the error persists, contact the administrator by writing to support infona. You can change the active elements on the page buttons and links by pressing a combination of keys:. I accept. The main object of the invention is to provide an all digital outphasing transmitter to be used in wireless communication and radar systems.
Another object of the invention is to provide an all digital outphasing transmitter with low combiner loss, which results in high efficiency at the transmitter output. RF outphasing transmitter facilitates the use of switch mode RF power amplifiers for an efficient amplification of amplitude varying signals.
However, the RF power combiner gives considerable loss when the peak to average power ratio of the applied signal is high enough. In such a situation, it is combining loss should be kept at a tolerable level. Therefore, according to the present invention, an outphasing transmitter with high efficiency is achieved. In a preferred embodiment of the present application, said mixing unit 4 comprises, at least one first mixer 9 for modulating the negative phased outphasing signal with the delta sigma modulated signal; at least one second mixer 10 for modulating the positive phased outphasing signal with the delta sigma modulated signal; at least one third mixer 11 for upconverting negative phased delta sigma modulated outphasing signal to an RF carrier frequency; at least one forth mixer 12 for upconverting positive phased delta sigma modulated outphasing signal to an RF carrier frequency; at least one signal generator 13 such as a clock generator or an RF signal generator for generating a carrier radio frequency signal to be used for upconversions.
Said mixing unit 4 preferably further comprises at least one first low pass filter 14 for filtering the output of the second mixer 10 in order to reject higher order mixing products of the negative phased delta sigma modulated outphasing signal and at least one second low pass filter 15 for filtering the output of the first mixer 9 in order to reject higher order mixing products of the positive phased delta sigma modulated outphasing signal.
In another preferred embodiment of the present application, said combiner 7 is in the form of a Chireix combiner. In this embodiment, Chireix combiner is one of the key components in the application. The combiner is designed together with the Class D RF power amplifier to get high combining efficiency. Because, the technique reduces time variation variance of the outphasing angle by reducing peak to average power ratio of the input signal, which concludes high combining efficiency.
In an exemplary embodiment of the present invention, an envelope signal is decomposed into two signals with lower peak to average power ratio by the decomposition unit 1. The criteria upon decomposition is based on locating the maximum probability distribution function at a required outphasing angle, which gives tolerable loss at the combiner 7. Tolerable loss is defined as the amount which does not compromise the efficiency that is gained with outphasing topology at the switched mode power amplifier.
Then, amplified signals are combined by said combiner 7. Time averaged power efficiency rather than maximum efficiency is more reasonable to qualify an RF transmitter in terms of power saving performance. Besides the peak to average power ratio, the probability density function of the input signal should be considered equally to comprehend the average efficiency performance.
After decomposition, delta sigma modulation is applied to the complementary signal. The primary advantages of using delta sigma modulation are the ability to send in-band noise out of the region of interest and convert the amplitude varying signal to a digital signal with constant amplitude. The former enhances the signal to noise ratio SNR ; while the latter is used to put the RF power amplifier into saturation to obtain the highest efficiency. Delta sigma modulation order and oversampling ratio are the two most critical parameters to tweak.
The Infona portal uses cookies, i. The portal can access those files and use them to remember the user's data, such as their chosen settings screen view, interface language, etc.
By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service.
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You can change the active elements on the page buttons and links by pressing a combination of keys:. I accept.
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