Welcome and Introduce - Recent Threads

HiFi5 NatureDSP RFFT output scaling issue for different FFT sizes

BR202501213237 — Thu, 01 Oct 2026 14:37:13 GMT

Hi,

I am working on standalone RFFT testing on Xtensa HiFi5 using the NatureDSP library.

I am testing different FFT sizes and comparing the fft_real32x32() output against my reference FFT data.

I am seeing the FFT output matches for 128, 512 and 2048 points, but does not match for 64, 256 and 1024 points.

My question is:

How should I correctly interpret/compensate the RFFT output for different FFT sizes and the returned fft_shifts value?

Is there any additional normalization or scaling required when comparing the HiFi5 fft_real32x32() output with a floating-point/reference FFT?

Also, has anyone observed this kind of behavior where:The FFT output matches for 128, 512 and 2048 points

with fft_real32x32() / ifft_real32x32() on HiFi5?

Any guidance on the correct FFT/IFFT scaling interpretation would be appreciated.

Platform: Xtensa HiFi5
Library: NatureDSP HiFi5
Functions: fft_real32x32() / ifft_real32x32()
Scaling option: 3

Thanks.

Welcome to the Community - introduce yourself!

Renu Vibha — Tue, 22 Jul 2025 06:49:09 GMT

Welcome to the Cadence Community Forums! We are thrilled to have you here!

We want you to know that this community has been created with you in mind to build professional connections, explore new ideas, discover alternative solutions, and stay updated on Cadence products, and much more.

To kickstart, what better way than introducing yourselves, right? Please feel free to use the questions, we’ve provided below (or a style all your own) and tell us a little about yourself!

Technology Interest/ areas of expertise, and what motivates you to actively participate in our forum discussions?
What are you hoping to learn from other members?

Once again, a warm welcome and we look forward to your contribution and success stories.

RE: Welcome to the Community - introduce yourself!

Renu Vibha — Wed, 19 Aug 2026 09:10:14 GMT

Hello Bharath,

Welcome to the forum, and thank you for the introduction.

It's great to have someone from STMicroelectronics, Singapore, join the community. Verification environments continue to evolve in complexity, and discussions around challenges, best practices, automation, coverage closure, performance optimization, and methodology improvements are always valuable.

We look forward to hearing your insights and experiences, as well as exchanging ideas on how to make verification workflows more efficient and scalable. Please feel free to start a discussion on any specific challenges or topics you'd like to explore.

Looking forward to engaging conversations and knowledge sharing.

RE: Welcome to the Community - introduce yourself!

BharathST — Wed, 19 Aug 2026 08:57:10 GMT

Hello everyone,

My name is Bharath Kumar Musku, and I am part of STMicroelectronics, Singapore.

As a member of this forum, I would like to discuss challenges in verification environments and share ideas for improvement.

Grid Settings

JE202605133419 — Tue, 07 Jul 2026 07:17:24 GMT

Currently, in my Allegro X, even after changing and applying grid settings for different layers and checking again, the intended settings are not reflected. Only the "All Etch" setting applies to all layers. However, this is changeable other versions such as 17.4.

RE: Welcome to the Community - introduce yourself!

PCBTech — Fri, 01 Aug 2025 04:03:12 GMT

Hi Harry,

Could you please provide more details on which step you're getting stuck? This will help us provide more targeted assistance.

Also, since this is product related query, we will be relocating this post to relevant product group.

RE: Welcome to the Community - introduce yourself!

HSID — Tue, 29 Jul 2025 15:28:20 GMT

I am trying to create a process for creating replicate circuits in Cadence Allegro 24.1 I have reviewed numerous times the Reuse flow in Allegro Design Entry CIS-Allegro PCB Editor document (RAK). I have not been able to complete this lab. I believe there are details that are not discussed and you are not sure what to do in order to proceed. Is there anyone who does create replicate circuits in Allegro Capture and Allegro PCB editor. I would like to see how a user does it. Eventually, Thank you in advance for any help and suggestions.