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Euso_4258576
Level 1
Level 1
5 sign-ins First reply posted First question asked

Hello,

I am currently measuring Tx Power of CYBT-353027-02 with LitePoint IQxel80 instrument.

However, I can merely measure Tx power aroud 8.7 dBm even though I set the power as maximum Tx power table 0x00 in cyBluetool as shown below.

Is there any issue on the BT module?

Could you look into this problem and suggest any of tryinig to do?

Below is the result of measured Tx power with power table 0x00.

pastedImage_2.png

Compared with measured Tx power and the power in data sheet, I can not increase Tx power up to 12dBm even though I set Tx power table as much as high (0x00).

pastedImage_4.png

(Data sheet Link : page 26, https://www.cypress.com/file/416356/download )

I used cyBluetool to control DUT and test configurations are like below.

pastedImage_0.png

The demo hello sensor application is installed on the BT module using WICED studio 6.2.

Thank you for your time and your support in advance.

Best regards,

Eunsung

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1 Solution
SheetalJ
Moderator
Moderator
Moderator
750 replies posted 500 likes received 500 replies posted

Hello Eunsung,

Most of our chipsets now support both class 2 and 1. For the latter, the power can be up to 10dBm typically.

Semiconductor process has advanced such that we need not include an external PA so as to do class 1. Instead the same die can now output up to 10dBm linearly. This is what you see in CYW20706.

Sometimes, we ascertained that if the chip is transmitting 12dBm, it may suffer from linearity problem, or also known as 1dB compression point.

View solution in original post

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7 Replies
SheetalJ
Moderator
Moderator
Moderator
750 replies posted 500 likes received 500 replies posted

Hello Eunsung,

Most of our chipsets now support both class 2 and 1. For the latter, the power can be up to 10dBm typically.

Semiconductor process has advanced such that we need not include an external PA so as to do class 1. Instead the same die can now output up to 10dBm linearly. This is what you see in CYW20706.

Sometimes, we ascertained that if the chip is transmitting 12dBm, it may suffer from linearity problem, or also known as 1dB compression point.

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Hi Cypress Team,

According to your datasheet(002-23132_CYBT-353027-02_EZ-BT_TM_WICED_R_MODULE), the max Tx out power is deascribed as +12dBm for Bluetooth Calssic.
Is It a typo?  and I can't make +12dBm TX power on CYBT-353027-02 EVAL board with current firmware ?

pastedImage_5.png

Thanks,

Inhwan Yoon

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The chip is capable of transmitting up to 12dBm, but it does not implied that it will do so for every transmission. The actual Tx power depends on the RSSI and application. If a device received a strong RSSI, then it means that the peer is nearby, and therefore it need not transmit a high power to reach it.

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Hi Cypress team,

I am testing it in the TX Test mode using CyBluetool as the following TX Test procedure. but the measured power was around 8dBm, my expected TX power was over 12dBm at maximun power index as described in Datasheet

I tested it not peering to Test equipment meaning not receving RSSI. I believe that the below test procedure is to see only TX performace not considering RX.

Do you have any idea to measure the maximum TX power(12dBm)?

Do I have to change Firmware to get it ?

************** Test procedure **************

1) Vendor-Specpic Commands

2) TX_Test

3) TX_Power_Level   -->  Specpic power Table index

4) Specpic power Table index --> 0x0  (I gusse this is the maximum power index)

**********************************************

Thanks,

Inhwan Yoon

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I believe index 0 means the max Tx power but it does not necessarily mean 12dBm. You may need another FW to demo this. Please relate your request to a Cypress (Korea) FAE.

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Hi Cypress team,

I think your comment that index_0 does not mean 12dBm is correct. I think it should be higer than 12dBm at index_0

Can you guide me how to contact KOR cypress team for another FW?

Thanks,

Inhwan yoon

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You may refer to the APIs in the below blog on how to configure the Tx power. Otherwise you may visit the Cypress Korea website where three is an email you can write to.

Configuring Transmit (Tx) power on the CYW20706

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