How to modify the frequency offset by software?

RE: How to modify the frequency offset by software?

rc766437 — Thu, 20 Dec 2018 02:56:36 GMT

Hi, I measure the 32Mhz cystal ,the reusult is 32.0006Mhz, 32768hz cystal didn't work, this is normal?

RE: How to modify the frequency offset by software?

rc766437 — Thu, 20 Dec 2018 02:53:53 GMT

Hi, that problem had solved?I have the same problem ,I don't know how to do...

RE: How to modify the frequency offset by software?

Sigurd — Fri, 17 Nov 2017 12:57:37 GMT

This offset is too big. Please make sure that you are using load capacitors that are within specifications. The load capacitors are the capacitors connected to the 32 MHz crystal ( C1 and C2 connected to the 32 MHz crystal in our reference design).

The value of these capacitors should satisfy this formula:

C1 = C2 = 2Cl - 4 pF

Cl: Load capacitance of the crystal (found in the crystal datasheet)

RE: How to modify the frequency offset by software?

Not2Good Sir — Fri, 17 Nov 2017 12:47:43 GMT

sorry. 150Khz

RE: How to modify the frequency offset by software?

Sigurd — Fri, 17 Nov 2017 12:43:47 GMT

150 KMHz? or 150 kHz ?

RE: How to modify the frequency offset by software?

Not2Good Sir — Fri, 17 Nov 2017 12:43:42 GMT

sorry, my write the wrong. in fact offset is 150Khz.

RE: How to modify the frequency offset by software?

Not2Good Sir — Fri, 17 Nov 2017 12:42:01 GMT

my write it wrong. in fact offet is 150Khz.

RE: How to modify the frequency offset by software?

Not2Good Sir — Fri, 17 Nov 2017 12:41:03 GMT

my write it wrong. In fact the offset is 150K.

i have another problem , uart input data, and BLE(peripherl) output to remote. my software max speed only 3K+, but my other bluetooth IC can do 7K/s, i don't why. connection interval and mtu all update.

Are there and other parameters affect it ?

software device is s132_nrf52_5.0.0 and IC is nrf52832. uart baud is 115200. MTU is 182. connection interval is 15ms.

RE: How to modify the frequency offset by software?

Sigurd — Fri, 17 Nov 2017 12:25:07 GMT

Hi,

With a constant, unmodulated carrier, an offset at 15 kHz is perfectly normal. I'm measuring an offset at 25kHz here. With a modulated carrier (when you are sending data) at 2402M Hz, you should see ±250 kHz offset.

RE: How to modify the frequency offset by software?

Not2Good Sir — Fri, 17 Nov 2017 07:45:35 GMT

sorry, i am so simple describe this problem. i describe this again. now , we are making own board. and we need have a best antenna performance. we use DTM demo in 14.1SDK to test this(Mode Transmit, Channel Single 0, payload model: Constant carrier, and Start test.), in my tester show own board transfer 2402M Hz offset +110K compare with normal 2402Mhz, so i know this is need modify hardware. but i want to know whether other tools can do it by software.

RE: How to modify the frequency offset by software?

RK — Wed, 15 Nov 2017 12:56:52 GMT

What frequency offset, how did you measure it, what do you mean by 15K? You need to ask a better question.