Table 4: Details of the resources for the different algorithms using the Altera FFT for the L5, E5a, E5b, and E1 signals, considering time multiplexing.

Implementation Function Logic usage Memory usage Multipliers usage
(ALM) (M20K) (DSP blocks)

3-FFT solution
(Figure 5(a))
3 FFTs (65 536 points) 3 × 2920 3 × 608 3 × 12
1 multiplier 0 0 2
Total 8760 1824 38

5-FFT solution
(Figure 6)
3 FFTs (32 768 points) 3 × 2758 3 × 264 3 × 12
1 multiplier 0 0 2
Total 8274 792 38

Proposed 9-FFT solution
(Figure 7)
3 FFTs (16 384 points) 3 × 2883 3 × 140 3 × 12
4 multipliers 0 0 4 × 2
Combinations for 28 0 0
Combinations for 64 0 1
Combinations for 64 0 1
2 memories (32 768 points) 0 2 32 0
Total 8805 484 46

Proposed 15-FFT solution 3 FFTs (8192 points) 3 × 2695 3 × 74 3 × 12
4 multipliers 0 0 4 × 2
Combinations for 112 0 0
Combinations for 224 0 4
Combinations for 224 0 4
4 memories (16 384 points) 0 4 16 0
Total 8645 286 52