It is correct that a 14-bit AD-Converter exhibits an effective signal to noise ratio of only 75dB. However, this value comprises for the whole bandwidth of 32MHz. By filtering appropriately and therefore reducing the bandwidth B, a process gain of P = 10*Log10(32MHz/B) can be achieved. With B=2400Hz, the process gain results in ca. 41dB, therefore the dynamic range is increased to 75 + 41 = 116dB.
Sunday, November 3, 2013
How is it possible to achieve a dynamic range of 112dB with a resolution of just 14 bits?
It is correct that a 14-bit AD-Converter exhibits an effective signal to noise ratio of only 75dB. However, this value comprises for the whole bandwidth of 32MHz. By filtering appropriately and therefore reducing the bandwidth B, a process gain of P = 10*Log10(32MHz/B) can be achieved. With B=2400Hz, the process gain results in ca. 41dB, therefore the dynamic range is increased to 75 + 41 = 116dB.
Difference between Digital and Analog Reciever
Most of today’s conventional receivers are based on the tripple
conversion concept. More often, DSP’s are placed in the third IF stage.
The most important performance criteria like intermodulation,reciprocal mixing, blocking and the selectivity of roofing filter can no longer be influenced by the DSP, because these parameters are already determined in the preceding analog stages.
Due to the large number of components it is difficult to achieve tight performance parameters during mass production.
In the digital receiver the full signal spectrum is fed directly to a high resolution A/D converter. All signal processing is made digitally, which is ideal as it relates to distortions and noise. Since algorithms are determined by software, uniform performance parameters are obtained. Another benefit of this technology is the high degree of functional flexibility. New functions can be added by simple software download.
Source : http://adat.ch/p1e_digitalrx.html
The most important performance criteria like intermodulation,reciprocal mixing, blocking and the selectivity of roofing filter can no longer be influenced by the DSP, because these parameters are already determined in the preceding analog stages.
Due to the large number of components it is difficult to achieve tight performance parameters during mass production.
In the digital receiver the full signal spectrum is fed directly to a high resolution A/D converter. All signal processing is made digitally, which is ideal as it relates to distortions and noise. Since algorithms are determined by software, uniform performance parameters are obtained. Another benefit of this technology is the high degree of functional flexibility. New functions can be added by simple software download.
Source : http://adat.ch/p1e_digitalrx.html
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