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Two important factors to consider while selecting an ADC are
1. The maximum msps
2. Dynamic range ( numer of bits)
If your information carrying RF signal has a band width of B, then you should select an ADC with at least 2B msps.
Next you consider the ACPR of the specific wireless standard you are working on. Say let it be TETRA, then the ACPR spec for adjancent channel is 60dBc and for alternate channel it is 70dBc. which means that your ADC should hae a dynamic range of atleast 70dB, ie minimum 12 bits (6.02N+1.76 dB)
A/D converter specifications for a receiver are fairly straightforward. you want as many bit's as you can afford. more bits translates to a higher dynamic range, which is a key receiver specification. In addition, with a higher dynamic range, you can ease the analog filtering requirements and the receiver gain control range.
At a minimum, you need to have enough dynamic range to digitize the complete dynamic range of the input signal.
• Receiver PAR. While this isn't an issue with a system such as GSM, with EDGE/WCDMA/WiMAX, the received signal has some amplitude variation that contains data, and needs to be captured. This Peak to Average ratio needs to be allowed for in the budget.
• Fading margin-The A/D converters needs to allow for some fading in the channel. This will be dependent on the system. For example, an system with non-mobile transmitters and receivers doesn't need as much fading margin as a highly mobile system such as a handset.
• Interfering channel. Having a higher A/D converter dynamic range allows the receiver filtering to move more into the digital domain from the Analog domain.
I know the ADC dynamic range in RF system is limited by block signal at adjacent channel. You can refer to RF system design book (search in this forum) to get more information
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