Altera NCO MegaCore Function Manuale Utente Scaricare il pdf (Pagina 28)

NCO IP Core Timing Diagrams

Figure 3-5: Single-Cycle Per Output Timing Diagram

clk

clken

phi_inc_i

reset_n

fsin_0

fcos_0

out_valid

42949673

0 -3 2057 41... 61.... 8148 10... 12... 13.... 15...

0 32767 32... 32... 32... 32... 31... 31... 30... 29... 28

All NCO architectures, except for serial CORDIC and multi-cycle multiplier-based architectures, output a

sample every clock cycle. After the clock enable is asserted, the oscillator outputs the sinusoidal samples at

a rate of one sample per clock cycle, following an initial latency of L clock cycles. The exact value of L

varies across architectures and parameterizations.

Note:

For the non-single-cycle per output architectures, the optional phase and frequency modulation

inputs need to be valid at the same time as the corresponding phase increment value. The values

should be sampled every 2 cycles for the two-cycle multiplier-based architecture and every N cycles

for the serial CORDIC architecture, where N is the magnitude precision.

Figure 3-6: Two-Cycle Multiplier-Based Architecture Timing Diagram

clk

clken

reset_n

fsin_0

fcos_0

out_valid

0 -3 41... 81... 12.... 15... 19... 22... 25...

0 32766 32... 32... 31... 30... 28... 26... 23... 20...

phi_inc_i

85899346

27... 29... 31... 32.... 32... 32... 32...

17... 13... 10... 61.... 20... -2... -6...

31...

-1...

29...

-1...

After the clock enable is asserted, the oscillator outputs the sinusoidal samples at a rate of one sample for

every two clock cycles, following an initial latency of L clock cycles. The exact value of L depends on the

parameters that you set.

Figure 3-7: Serial CORDIC Timing Diagram with N = 8

clk

clken

reset_n

fsin_0

fcos_0

out_valid

0 3 1404

0 2047

phi_inc_i

31457

-20112043 1574 257 -1201

1490 -383129 -1308 -2030 -16572046

Note:

The fsin_0 and fcos_0 values can change while out_valid is low.

UG-NCO

2014.12.15

NCO IP Core Timing Diagrams

3-11

NCO IP Core Functional Description

Altera Corporation

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