8.2.1.2 Detailed Design Procedure
Use the following steps to design the RF receiver:
- Use the signal-center frequency and signal bandwidth to select an appropriate sampling rate (DEVCLK frequency) and decimate factor (x / 4 to x / 32).
- Select the sampling rate so that the band of interest is completely within a Nyquist zone.
- Select the sampling rate so that the band of interest is away from any harmonics or interleaving tones.
- Use a frequency planning tool, such as the ADC harmonic calculator (see the 开发支持 section).
- Select the decimation factor that provides the highest factor possible with an adequate alias-protected output bandwidth to capture the frequency bandwidth of interest.
- Select other system components to provide the needed signal frequency range and DEVCLK rate.
- See Table 1 for recommended balun components.
- Select bandpass filters and limiter components based on the requirement to attenuate unwanted signals outside the band of interest (blockers) and to prevent large signals from damaging the ADC inputs. See the Absolute Maximum Ratings table.
The LMK048xx JESD204B clocking devices can provide the DEVCLK clock and other system clocks for ƒ(DEVCLK) < 3101 MHz.
For DEVCLK frequencies up to 4 GHz the consider using the LMX2581 and TRF3765 devices as the DEVCLK source. Use the LMK048xx device to provide the JESD204B clocks. For additional device information, see the 相关文档 section.