ANAN 10 Question

[W1AEX]

Brett,

It looks like the newest is 1.3 for the 10E.

Rob - W1AEX

https://apache-labs.com/instant-downloads.html

[N2DTS]

Another thing I do not get is the radio seems to have very little or no latency on CW.
In the old flex stuff the sidetone was generated by the radio and reflected the delay through the system, and it was just like voice, very hard to send when the sidetone was .5 or more second behind the key.
The ANAN seems to have no real delay and seems to work like a normal rig on CW.

[AB2EZ]

Brett

With my ANAN-10, I measure:

1.  Delay between pressing the paddle, and the monitor tone produced at the front panel headphone jack: not perceptible (no problem sending CW at 25 WPM)

2. Delay between the monitor tone produced at the front panel headphone jack and the RF output (as produced by my off-air monitor): 16 milliseconds.

This is controlled by the "key down" CW delay setting in the General => Options setup window. I have this set to 16 milliseconds

If I set the "key down" CW delay to 0 milliseconds, then there is 0 milliseconds of measured delay between monitor tone produced by the front panel  headphone jack and the RF output (as produced by my off-air monitor).

In CW mode (regardless of the setting of the DSP CW "transmit buffer" size), it appears that there is no narrow bandpass digital filtering being done on the transmitted signal. Essentially, when the key is closed, the high speed FPGA produces the digital representation of a pure tone at the desired RF frequency... and that feeds directly into the D/A converter and the RF amplifier chain.

In SSB or AM mode, there is delay (as previously discussed in this thread) between the audio input and the ANAN10E's "monitor" output (or, an external off-air monitor)... because (among other things) the monitoring is done after the steep skirt bandpass digital filtering has been applied to the digital representation of the output signal. That delay depends upon the number of samples being buffered in the bandpass digital filter (the DSP "transmit buffer" length), and on the delays of other buffers that exist in the transmit chain. With the DSP bandpass digital filter buffer set to 512 samples (in my case), that accounts for 512 samples / 48000 samples per second = 10.7 milliseconds of delay. Since the total delay (in my case) is around 50-55 milliseconds, the other buffers are adding about 40-45 milliseconds of delay. I'm not yet clear on what those other buffers are.

Stu

Feedback received this afternoon from Warren, NR0V, via the Apache Labs Yahoo group:

Hi Stu,

 Some months ago we moved the transmit CW generation from software to firmware.  This was done for just the reason you observed, i.e., to eliminate latency.  The CW Buffer setting for TX is no longer relevant for you.  No narrowband filtering is needed as (1) the waveform can be precisely formed with nice raised-cosine edges, and (2) everything is digital and the calculations are very precise.

 73,
 Warren  NR0V

[N2DTS]

Thanks for the info Stu.
CW used to be a problem with the Flex stuff, but the 10E works very well.

If you monitor yourself in headphones (built in monitor) it is not too delayed to speak normally?

[AB2EZ]

Brett

As I have been told by one of the creators of HPSDR and the ANAN transceiver design:

On phone, the output of the ANAN's monitor is not a true representation of the modulation of the outgoing transmitted AM signal. This is an idiosyncrasy of the current design... and has (among other things) to do (if I understand it correctly) with the fact that the PureSignal pre-distortion correction is added before the monitoring point... but the monitor audio signal is obtained from the digital representation of the transmitted signal (before the D/A converter). It is not obtained from the receiver of the ANAN (which would add more latency).  So, what you hear with the monitor is the predistorted modulating signal... which is not subsequently compensated by the distortion of the RF amplifier.

I must admit that I don't know all of the details of this, but if I play a prerecorded audio clip into the ANAN's audio input (my own voice, calling CQ40) ... what I hear sounds different on the ANAN's monitor output v. my own off-air (REA) monitor. My off-air monitor sounds better.

With the latency now being only 50 milliseconds, I can monitor my AM signal with my REA off-air monitor while I am talking... and (after getting used to this slight delay) it is marginally acceptable. However, for listening to my own signal to check the quality of the transmission, I prefer to use a prerecorded audio clip as input to the ANAN. I usually don't monitor my transmitted signal in real time any more.

Stu

[N2DTS]

Thanks again Stu.
Then it sounds like everything is working normal here, I can get it to where I can monitor, the delay is just fast enough on the two smallest buffers that I can almost speak normally, that is its so quick its not impossible.

Any idea what happened with the firmware change from 1.2 to 1.3?

[N2DTS]

Its in the for sale section here.

So $1000.00 for a 3 watt radio with a lot of latency seems like a poor investment, I still like the SDR-IQ better as a band scope and a receiver.
A 3 watt transmitter with a lot of delay in it I have no use for.

Let me know what you want for it as I'm looking for a second one.

Nigel

[W3RSW]

Brett,
VK6PH the author is referenced in the Anan download if you didn't already know.

One can use the hpsdr svn to actually compare code changes line by line once gaining familiarity with the process.

http://svn.tapr.org/repos_sdr_hpsdr/trunk/Hermes/Release/

Hence:
http://svn.tapr.org/repos_sdr_hpsdr/trunk/Hermes/Release/Notes/Change.txt

And here's all the contributors. Fascinating wandering through the list. I've hit DL3HVH a bunch for CuSDR info and download.
http://svn.tapr.org/repos_sdr_hpsdr/trunk/

Glad you got your latency identified.
Same as Stu, I think I mentioned earlier that there was a very slight delay on SSB monitoring via phones from front panel output when using the Anan monitor compared with internal head speaking voice. --Just large enough to sound like a small amount of echo as if it were intentional.

Stu, than you tons for clear and concise explanations. It's been a lot of fun learning the ins and outs of the Hermes derived rigs.  I originally bought the Hermes board simply betting on CuSdr being Xmit completed a couple of months ago and then a Hammond case, but then decided to quickly exchange for the A 10. Supplier was game and quickly credited Hermes cost to the 10.

[N2DTS]

Thanks Rick.
I am not enough of a geek to get into the software that much, although it must be great fun to play with if you know how.

I had high hopes for the radio thinking the Ethernet interface and some of the work being done in the FPGA would reduce the latency to almost nothing, but it has not.
Perhaps on a really fast computer it could.

As it is, the ANAN is just a bit faster then the sdr-iq with its USB delay, and not quite as fast (or the same) as the early Flex stuff.

The QS1R was the same as the sdr-iq (in latency), along with all the other USB based radios.
Maybe one of the new RF Space receivers will be low latency, they all use Ethernet.

I will not be happy till its real time, and for a radio, I want 100 watts and a built in tuna.
Like all solid state radios, the 10E is picky about SWR and will not drive my 4x150's as it is, and will not even work into my antenna's if its raining.
Self protects above about 1.8 to 1.