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Customer Comment ...
"Micro Linear used ADS to behaviorally model a direct FSK modulator at 5.8GHz. Since the modulator was based on a fractional-N synthesizer with a two-port VCO, we were concerned about the interaction between the modulation signal and loop filter of the fractional-N synthesizer.
ADS gave us the capability to run mixed signal simulations that involved both analog blocks, such as the loop filter, and digital blocks such as the delta-sigma modulator and Gaussian pulse-shaping filter. These simulations were crucial in optimizing important design parameters such as PLL configuration and loop bandwidth.
Moreover, the simulation helped us to gain much better insight into the influence of the DSM architecture on the quantization noise of the synthesizer. After verifying our digital blocks at the algorithm level using Ptolemy, we used the HDL co-simulation capability of the ADS to validate our Verilog codes for the DSM and the pulse-shaping filter. The chip was built in a SiGe BiCMOS process and we were impressed by how closely lab results matched ADS simulation."
- Shayan Farahvash, RFIC Systems Architect, Micro Linear Corporation, San Jose, California, USA
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