Analog Devices ADRV9001 User Manual page 199

Reference Manual
RECEIVER DEMODULATOR
j2πf t n
A × e , n = 0, 1, 2, . . .
f s
where:
A is the signal magnitude.
f is the tone frequency.
t
f is the sampling frequency.
S
The output of the frequency discriminator (FD) is D × 2f
Narrowband Programmable FIR
The narrowband programmable FIR in rxnbdem performs the pulse shaping filtering or low-pass filtering at the output of the frequency
discriminator. This module can be bypassed.
The narrowband programmable FIR supports up to 128 taps. Each tap is 24 bits in width, including the sign-bit, and can load only one set of
customized FIR profiles.
Resampler
Resampler in rxnbdem adjusts the sampling phase of the IQ or FD signal. This module can be bypassed.
intermediate samples between every two input samples according to the resample phase parameter, μ, where μ ≤ 0.5.
The Figure 176 shows the functional diagram of the resampler. The resampler resamples the incoming received signal by reconstructing
In the frequency domain, the ideal digital resampler has the transfer function, as shown in the following equation:
H jω, μ =
ideal
where:
B is the maximum bandwidth of the input signal.
x
Filtered by the ideal resampling filter, the input signal, x(kT
Scanning the sampling phase μ from 0 to 0.5, the maximum magnitude difference of the frequency transfer function between the Resampler
and the ideal digital resampler is collected and plotted at the upside of the
downside of the Figure 177.
The resampler can be used in both the wideband and narrowband modes.
analog.com
/f while the output Mag2 is A
t S
T × e , ω/2π ≤ B
jωμT S
s
do not care, ω/2π > B
), is converted to the output signal y(kT
S
Figure 176. Functional Diagram of the Resampler
2
.
x
x
Figure 177. The maximum phase error is collected and plotted at the
ADRV9001
) = x((k + μ) × T )
S S
Rev. 0 | 199 of 351
(6)