Difference between revisions of "NVGate DSP computation SPU"

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= Force DSP=
= Force DSP=


On force DSP (and also for normal DSP...), the number of SPU change according to the max sampling frequency. We have:
On force DSP (and normal DSP), the number of SPU change according to the max sampling frequency.
 
The more you have data to analyse (high sampling frequency), the less you have power computation (SPU).
We have:


{| class="wikitable"
{| class="wikitable"
|-
|-
! Sampling Frequency in kHz !! Number of SPU / DSP (normal or force)
! Sampling Frequency (kHz) !! Number of SPU / DSP (Normal or Force)
|-
|-
| 102.4 || 6
| 102.4 || 6
Line 37: Line 40:
| 401 ||1 || 0.33
| 401 ||1 || 0.33
|-
|-
| 801 || 1.25 || 0.18
| 801 || 1.25 || 0.18 (yes<sup>1</sup>)
|-
|-
| 1601 || 1.5 || 0.75
| 1601 || 1.5 || 0.75
Line 50: Line 53:
|}
|}


Envelope: 51.2kHz - 401 lines : 2 SPU per channel on force DSP
Envelope: 401 lines : 2 SPU per channel on force DSP
 
Zoom: 401 Lines : 0.66 SPU per channel on force DSP.
 
1) Computing is not linear and FFT 801 lines is the most optimised for DSP
 
===Recorder===
 
{| class="wikitable"
|-
! Recorder Sampling frequency (Hz) !! Normal DSP: SPU / channel !! Force DSP: SPU / channel
|-
| 51200 or upper || 1 || 0.66
|-
| 32768 || 0.66 || 0.44
|-
| 25600 || 0.5 || 0.33
|-
| 16384 || 0.33 || 0.22
|-
| 12800 || 0.25 || 0.167
|-
| Else || 0.125 || 0.083
|}
 
===Octave===
 
{| class="wikitable"
|-
! Octave !! Normal DSP: SPU / channel !! Force DSP: SPU / channel
|-
| 1/3 || 3 || 1
|-
| 1/12 || 6 || 2
|-
| 1/24 || 12 || 4
|}
 
===OVA===
 
{| class="wikitable"
|-
! Normal DSP: SPU / channel !! Force DSP: SPU / channel
|-
|  1 || 0.25
|}
 
===TDA===
 
 
{| class="wikitable"
|-
! Normal DSP: SPU / channel !! Force DSP: SPU / channel
|-
|  3 || 1.5
|}
 
===SOA===
 
SPU computation for SOA is more complex because it depends of maximum speed, resolution and frequency. Also force DSP computation is not linear.
 
Force DSP will improve the SPU computation by reducing between  2.5 and 5 to compare with normal DSP.


Zoom: 51.2kHz - 401 Lines : 0.66 SPU per channel on force DSP.
(@20kHz - 401 lines, we need a maximum of 3 SPUs with normal DSP)


= Normal DSP=
= Normal DSP=
SPU computation for normal DSP : OR34 V1 - Or35V1 - OR36V1 OR36V22 (normal DSP) - OR38V1 - OR38V2 (Normal DSP).
SPU computation for normal DSP : OR34 V1 - OR35V1 - OR36V1 OR36V2 (normal DSP) - OR38V1 - OR38V2 (Normal DSP).


Because of the linearity of the computation, we simplify by saying:  1DSP = 12 SPU (no matter the sampling frequency). This allow a simplification for SPU computation. So we can deduce:
Because of the computation linearity, we simplify by saying:  1DSP = 12 SPU (no matter the sampling frequency). This allow a simplification for SPU computation. So we can deduce:


==FFT==
==FFT==

Latest revision as of 13:22, 29 June 2023

Force DSP

On force DSP (and normal DSP), the number of SPU change according to the max sampling frequency.

The more you have data to analyse (high sampling frequency), the less you have power computation (SPU). We have:

Sampling Frequency (kHz) Number of SPU / DSP (Normal or Force)
102.4 6
65.536 9
51.2 12
32.768 18
25.6 24
16.384 36
12.8 48
6.4 96
3.2 192
1.6 384

FFT

According to the architecture of force DSP, the SPU computation per channels is not linear. So we have the following table for real time SPU computation :

Number of FFT lines Normal DSP: SPU / channel Force DSP: SPU / channel
401 1 0.33
801 1.25 0.18 (yes1)
1601 1.5 0.75
3201 2 0.8
6401 3 2
12801 4 2
25601 6 3.5

Envelope: 401 lines : 2 SPU per channel on force DSP

Zoom: 401 Lines : 0.66 SPU per channel on force DSP.

1) Computing is not linear and FFT 801 lines is the most optimised for DSP

Recorder

Recorder Sampling frequency (Hz) Normal DSP: SPU / channel Force DSP: SPU / channel
51200 or upper 1 0.66
32768 0.66 0.44
25600 0.5 0.33
16384 0.33 0.22
12800 0.25 0.167
Else 0.125 0.083

Octave

Octave Normal DSP: SPU / channel Force DSP: SPU / channel
1/3 3 1
1/12 6 2
1/24 12 4

OVA

Normal DSP: SPU / channel Force DSP: SPU / channel
1 0.25

TDA

Normal DSP: SPU / channel Force DSP: SPU / channel
3 1.5

SOA

SPU computation for SOA is more complex because it depends of maximum speed, resolution and frequency. Also force DSP computation is not linear.

Force DSP will improve the SPU computation by reducing between 2.5 and 5 to compare with normal DSP.

(@20kHz - 401 lines, we need a maximum of 3 SPUs with normal DSP)

Normal DSP

SPU computation for normal DSP : OR34 V1 - OR35V1 - OR36V1 OR36V2 (normal DSP) - OR38V1 - OR38V2 (Normal DSP).

Because of the computation linearity, we simplify by saying: 1DSP = 12 SPU (no matter the sampling frequency). This allow a simplification for SPU computation. So we can deduce:

FFT

Computation SPUs:

Bandwidth Fdec Resolution Envelope Zoom SPU/Channel
for Real-time
SPU/Channel
for non Real-time
20k 1 401 No No 1 0,5
10k 1 401 No No 0,5 0,25
Nk 1 401 No No =N/20 =N/40
10k 2 401 No No 1 1
5k 4 401 No No 0,8 0,6
2k 10 401 No No 0,6 0,6
1k 20 401 No No 0,5 0,6
Lower
than 1k
Higher
than 20
401 No No 0,5 0,5
20k 1 401 and
below
No No 1 0,5
20k 1 801 No No 1,25 0,5
20k 1 1601 No No 1,5 0,5
20k 1 3201 No No 2 0,5
20k 1 6401 No No 3 0,5
20k 1 401 No No 1 0,5
20k 1 401 No Yes 2 1,5
20k 1 401 No No 1 0,5
20k 1 401 Yes Yes 3 3



Fft sampling.png

SOA

Computation SPUs:

Bandwidth (Hz) Decimation factor Resolution SPU/Channel
20 k 1 401 3
10 k 1 401 1,5
N k 1 401 =(N*3)/20
10 k 2 401 2
5 k 4 401 1,3
2,5 k 8 401 1,1
1,25 k 16 401 0,9
625 32 401 0,8
313 64 401 0,7
156 128 401 0,6
78 256 401 0,6
20 k 1 401 and below 3
20 k 1 801 3,25


Order analysis 19.png

Sampling Frequency: set in Front-End/Inputs settings/Input sampling

FFT Bandwidth: set in FFTx/FFT analysis/range

==

Octave:

Bandwidth Fdec Reso SPU/Channel
for Real-time
25.6k 1 1/3rd 4
20k 1 1/3rd 3
12.8k 1 1/3rd 2
10k 1 1/3rd 1,5
20k 1 1/3rd 3,0
10k 2 1/3rd 2,0
5k 4 1/3rd 1,25
20k 1 1/1 1,5
20k 1 1/3rd 3
20k 1 1/12th 6
20k 1 1/24th 12


Octave 01.png

Sampling Frequency: set in Front-End/Inputs settings/Input sampling

1/N Oct Bandwidth: set in OCT/FFT analysis/range

OVA

Bandwidth SPU/Channel
for Real-time
25,6k 1,25
20k 1
12,8k 0,75
10k 0,5

The overall acoustic levels analysis requires 1 SPU per channel at 20 kHz bandwidth. The number of required SPUs is directly proportional to the analysis bandwidth (i.e. the sampling frequency divided by 2.56).