From: Steven Singer <steven.singer@csr.com>
To: bluez-devel@lists.sourceforge.net
Subject: Re: [Bluez-devel] TPL (transmit power level)
Date: Tue, 22 Feb 2005 16:59:33 +0000 [thread overview]
Message-ID: <421B64F5.8090100@csr.com> (raw)
In-Reply-To: <de33c8be050221181635c1a751@mail.gmail.com>
Flávio wrote:
> One more question about this topic.
> In bluetooth core says that the range of the tpl (transmit power
> level) is between -30<= N<=20 and the step (resolution) is one
> unit,
Where does it say that the step is one unit? It might say that the
units for this value are dBm.
> but when i execute the command hci_read_tpl (transmit power
> level) all the values that i receive are:
> 17 ; 14 ; 10 ; 6 ; 2 ; -2 ; -6 ; -9 and no more :(
> why?
This is completely as expected.
If you look right at the start of the Bluetooth spec in the radio
specification under transmitter characteristics, it says:
The power steps shall form a monotonic sequence with a maximum
step size of 8 dB amd a minimum step size of 2 dB.
The easiest way for a manufacturer to meet this specification is with
a preprogrammed set of levels.
A device isn't obliged to use the full range. The radio spec also says:
Power control capability under +4 dBm is optional.
Your chip appears to go down to -9 dBm which exceeds the spec.
> it´s something about Bluez or is the Firmware (of my dongle usb)
> that realy gives that values for tpl?
The firmware of the dongle reports the values.
Tour device is completely within spec.
- Steven
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next prev parent reply other threads:[~2005-02-22 16:59 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-02-16 12:25 [Bluez-devel] TPL (transmit power level) Flávio
2005-02-21 23:24 ` Marcel Holtmann
2005-02-22 2:16 ` Flávio
2005-02-22 2:28 ` Marcel Holtmann
2005-02-22 3:09 ` Flávio
2005-02-22 3:16 ` Marcel Holtmann
2005-02-22 14:43 ` Flávio
2005-02-22 15:08 ` Marcel Holtmann
2005-02-22 15:20 ` Flávio
2005-02-22 16:59 ` Steven Singer [this message]
2005-02-22 19:20 ` Flávio
2005-02-23 14:43 ` Steven Singer
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