This core implements a configurable tap fractionally-spaced blind adaptive equalizer based on the constant modulus algorithm (CMA) for quadrature amplitude modulation (QAM) signals. Its more important features and implementation example results are shown below.
CMA Equalizer core features:
- Configurable number of taps from 4 to 32
- Programable initial conditions
- Valid for BPSK, QPSK and 16-QAM modulations
- Variable number of samples per symbol
Implementation example
The CMA Equalizer core was implemented in a Xilinx Virtex-6 device (speed grade -3) and an Altera Stratix-IV (speed grade -4) device with the following features:
- Number of taps = 16, 24 and 32
- Modulation = QPSK
- 17 bits input and output data
- 1 and 2 samples per symbol
The following table shows the implementation results for the Virtex-6 device:
|
16-taps
|
24-taps
|
32-taps
|
|
|---|---|---|---|
|
Number of slices
|
1,429
|
1,930
|
2,765
|
|
Number of DSP48E1s
|
54
|
78
|
102
|
|
Max. Clock Frequency
|
72.2 MHz
|
72.0 MHz
|
69.4 MHz
|
|
Throughput @1sps
|
14.4 Msps
|
14.4 Msps
|
13.8 Msps
|
|
Throughput @2sps
|
7.2 Msps
|
7.2 Msps
|
6.9 Msps
|
The following table shows the implementation results for the Stratix-IV device:
|
16-taps
|
24-taps
|
32-taps
|
|
|---|---|---|---|
|
Total LABs
|
441
|
656
|
896
|
|
DSP block 18-bit elements
|
108
|
156
|
204
|
|
Max. Clock Frequency
|
87.9 MHz
|
79.4 MHz
|
78.6 MHz
|
|
Throughput @1sps
|
17.5 Msps
|
15.8 Msps
|
15.7 Msps
|
|
Throughput @2sps
|
8.7 Msps
|
7.9 Msps
|
7.8 Msps
|