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I am using an ICOM IC-7610 transceiver and ICOM has released a software update to provide DPD (Digital Per-Distortion) in addressing non-linearity in RF power amplifiers.

Is this something which needs addressing with the Palstar LA-1K ?

Thomas NE7X...

Digital Pre-Distortion (DPD)?is a technique to increase linearity or compensate for non-linearity in power amplifiers.??are critical in communication systems and it is crucial to improve their efficiency and overall performance. DPD is a cost-effective linearization technique which aims to provide improved linearity, better efficiency, and take full advantage of power amplifiers.

Digital Pre-Distortion applies inverse distortion, using a pre-distorter, at the input signal of the PA to cancel the distortion generated by the power amplifier. This requires knowing the PA characteristics accurately with effective implementation for successful DPD functioning. Proper implementation can show improvements of up to 40% in PA efficiency used in wireless base stations.

On Sat, Nov 25, 2023 at 11:24 AM, Thomas NE7X wrote:

I am using an ICOM IC-7610 transceiver and ICOM has released a software update to provide DPD (Digital Per-Distortion) in addressing non-linearity in RF power amplifiers.

Hi Thomas,

Looking at this ICOM page it sure sounds like the DPD thing applies solely to their IC-PW2 amp when paired with their IC-7610 transceiver.? As such, it's doubtful ICOM would share its proprietary technology with Palstar to enhance LA-1K compatibility with the IC-7610 transceiver.

73
Ray
KJ5MI

The Palstar LA-1K incorporates a rear (RCA jack) labeled, and included in the instruction manual, as::
? P U R E S I G N A L : S a m p l e @ + 1 0 d B m @ 1 k W o u p u t ( R e a r P a n e l )

I don't recall any information in the Instruction Manual as to the exact setup or operation of this output, although I suppose the above label is reasonably descriptive.

"Pure Signal" has been around for some time, with limited application.? I had assumed it was based on an open standard that could be applied across equipment from various manufacturers.? Of course, there is no reason any one amateur radio supplier would find it desirable to use it, versus their own proprietary method.? One only needs to suffer with D-Star, System Fusion, and DMR to see that!!

So I guess the question would be:? Does the ICOM Pre-Distortion feature follow the Pure Signal standard, and it not, can they be made to play together?

The part of the Digital Pre-Distortion system in the amplifier is only a RF sampler (or attenuator) that provides a very small feedback signal from the amp to the transceiver. All the DPD work appears to be performed in the transmitter. If the input level required by the ICOM transceiver is +10dBm (10mW), DPM could be provided to the LA1K by the ICOM transceiver. DPD appears to be a very slow feedback system that learns the corrections, rather than provides an immediate correction like a normal feedback system. This keeps the feedback system stable because of the long delays inside of the feedback loop would cause instabilities.

Maybe this provides some insight.
73
.... Bill K3HZP

On Sun, Nov 26, 2023 at 03:22 PM, Bill K3HZP wrote:

If the input level required by the ICOM transceiver is +10dBm (10mW), DPM could be provided to the LA1K by the ICOM transceiver.

This pre-release information makes claim that "The IC-PW2 has succeeded in realizing the world’s first DPD as a linear amplifier for amateur radio in combination with the IC-7610."

Being the "world's first" sure makes it sounds like said ICOM DPD isn't exactly identical to the PureSignal approach that has been around for years.

This ICOM page has a nice clear pic of their DPD feedback cable providing the needed connection between the IC-7610 and IC-PW2.

Perhaps, owners of PureSignal-equipped LA-1K with IC-7610 (new DPD firmware installed) as the exciter can share their findings with the rest of us.

73
Ray
KJ5MI