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New High Speed DACS from Analog Devices . |
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CommAgility module provides multicore DSP and FPGA performance for WiMAX and LTE |
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Sundance Goes Beyond 3G With ‘Radio Giga’ Reference Platform. |
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BittWare Announces Reconfigurable FPGA AMC Module. |
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Lyrtech selected by Texas Instruments as a member of the Design House Network |
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New Blackfin Processors Offer Cheaper, Lower Power Solutions |
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| POSIX® API Extends DSP/BIOS™ Reach for More DSP Applications by Peter Petrov, FADATA, AD and Andrew Ferrari, EWA Technologies. |
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Digital Signal Processor (DSP) applications are increasingly complex, advanced systems, often served by embedded Real Time Operating Systems (RTOS) to manage their size, numerous tasks, and external interfaces. Source code portability, a progressively more important requirement for these systems, is being mandated for commercial applications and government contracts.
Today, wireless networks and devices must be compatible over a wide variety of changing communication standards. more>>
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Baseband, Passband Signals and Amplitude Modulation by Charan Langton
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The frequency domain representation of a Product Modulator or a mixer has a curious quality that instead of producing the products of the input frequencies which is what we really want, it produces sums and differences of the frequencies of the two input signals in both the positive and negative frequency domains. Is this a problem? The answer depends on what we want to do with the output. In most case if no non-linearity is present, we can predict exactly where these components will lie and we can filter out what we do not want.
What if the carrier frequency source in a product modulator is not perfectly stable? In this case, each deviation frequency will also produce its own sum and difference frequencies with the baseband signal. These are called spurs and are inherent to the mixer process. In addition phase oscillations of the carrier also affect the output. For this reason simple mixer modulators and demodulators do not work well and further complexity in form of phase lock loops etc. is introduced into the receiver design. more>>
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