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@rocco123456
This exciter recognizes S/P-DIF format, and works via Port C (optical digital interface).
Can’t guarantee S/P-DIF via Port A, due to different termination.
I haven’t tested this, but I believe it should work too.@Dj Buik
Legal or pirate, equally should comply with basic requirements like spurs, harmonics, etc.
Being pirate is one problem. Why causing bigger problems – like interference to aeronautical frequencies? 🙂
Anyway, it will be released as 30W exciter (although can give up to 80W, but don’t tell anyone… 😉 )
I have not decide it’s final price yet.@Leif
Beer? Cheers! 😀@yorkie98
It’s a separate process, it has to pass this too.@yorkie98:
No, Port C is AC-coupled.@Dj Buik:
After ETSI compliance test (around February I guess), can be released to relevant market.
Depending on the market interest, will go for FCC certification too.Last week, I have finished the PCB design and now I’m waiting for the PCB samples to arrive.
I believe after Xmas will have a 30W working prototype (which goes to camclone).
Then I will make two more, one for Leif (0.5W) and one for yorkie98 (30W).They will have three audio ports:
- Port A: Digital electrical interface, XLR female connector, balanced 110 Ohm, transformer isolated.
- Port B: Digital optical interface, F05 connector female (Toshlink – 5 mm).
- Port C: Analog electrical interface, 2 x XLR female connectors, balanced 600 Ohm.
Audio operational modes:
- MONO, with audio source selectable from:
- Port A (Digital L/R mixing, in AES-EBU up to 24bit 96kHz format)
- Port B (Digital L/R mixing, in AES-EBU up to 24bit 96kHz format)
- Port C (Analog Left / Right mixing, sampled at 24bit 96kHz)
In this mode, the internal DSP stereo coder is disabled.
. - STEREO, with audio source selectable from:
- Port A (Digital L/R, in AES-EBU up to 24bit 96kHz format)
- Port B (Digital L/R, in AES-EBU up to 24bit 96kHz format)
- Port C (Analog Left / Right, sampled at 24bit 96kHz)
In this mode, the internal DSP stereo coder is enabled.
. - EXT BASEBAND, with audio source selectable from:
- Port A (Digital L/R, in AES-EBU up to 24bit 192kHz format) <— D-MPX
- Port B (Digital L/R, in AES-EBU up to 24bit 192kHz format) <— D-MPX
- Port C (Analog Left-jack only, sampled at 24bit 192kHz) <— A-MPX
In this mode, the internal DSP stereo coder is disabled.
NOTES:
Port A and Port B cannot be used simultaneously.
Port C can be triggered by external event to replace Port A or B input.Let’s see if Santa Claus exists… 😆
The D-MPX is ready, blame the "analog-MPX" input please!
It took me longer than estimated, sorry for that… 🙁This Tuesday-Wednesday I am expecting one last ADC Evaluation Board to test.
After this, I’m done, and can start prototypes.Thank you for your patience! 😳
@ricardogerassi
I am seeking proposals about digital STL. Can you contribute? 🙂
What about no-Microblaze, but pure, faster VHDL?@yorkie98
Of course optical interface is better, but if your concern is galvanic isolation, the electrical AES3 input has 1:1 transformer.
As Boki already mentioned, there are not so many cards with optical out @ 192kHz. 🙁[quote author=”yorkie98″]Sigmacom, which standards of digital input are you planning to include? Optical SPDIF, Coaxial SPDIF, AES/EBU?
To please everyone, you will most likely need all 3 but I would suggest that consumer optical would be the most commonly used.Really looking forward to trying the prototype.. 😀[/quote]
Well, it seems you’re lucky! 🙂 It provides:
– 1 digital electrical interface: XLR connector (selectable Unbal.75 / Bal.110 Ohm)
– 1 analog electrical interface: XLR connector (selectable Unbal.75 / Bal.110 Ohm)
– 1 optical interface: F05 connector (Toshlink – 5 mm)It recognize AES3 and S/PDIF at any input (electrical or optical) up to 192k.
[quote author=”rocco123456″]Hello Boys…Hello Leif….!!!
Any news about Digital MPX Transmitter prototype…?????
Honever… i’im working on a spdif-qpsk converter…and qpsk-spdif converter…..to convert analogic link in digital link….Thank you…
Rocco..
Look at http://www.elber.it/en/schede-fm-audio- … .php?id=31[/quote]
At the end of this week, maybe beggining/mid of next week, it will be completed.Beside the D-MPX input, will also have analog MPX input, as some people requested.
I disagree with that, and I suggest to use D-MPX of course…About your digital STL project, I’d love it if you use 64 or 256-QAM and reduce occupied BW.
That kind of STL is in my next plans, if you can do it, I would like to co-operate! 🙂[quote author=”JesseG”]Call me crazy, but eventually the signal has to be turned into analog to become electro-magnetic in nature and amplified for the antenna, etc, etc… And I was under the impression that’s what the DDS exciter sigmacom is working on does. Gets the digital signal as far down the path as will ever be possible within the FM design, and delivers a signal higher quality than any known method we currently have.
Am I wrong?[/quote]
No JesseG, you’re not wrong… 🙂
Even the digital modulation schemes like QPSK, QAM etc, become "analog" on air. The difference from FM, is that they have specific and discrete "analog" states.
The QPSK modulation for example, has only four and predefined discrete states (phase variation), while FM can have infinite states. Thus, the QPSK receiver cannot be easily confused and misinterpret between these 4 states, plus the use of error-correction techniques that elevate the fidelity of the transmitted information.The "infinite possible states of FM modulation", luckily for us, is reduced down to ~16.8 million different states for a 24-bit audio sample. My DDS can accurately represend ~4.3 billion different states on air, and with extra programming + H/W can go up to ~18 quintillion states. The audio samples may arrive at a rate of 48.000 samples/sec per channel, but the DDS updates the output frequency at a rate of 540.000 times/sec. If I didn’t had the internal MPX encoder, it could go >1.000.000 times/sec.
So, about the ‘on air’ representation accuracy of the incoming digital audio, I think we’re good… 🙂
Hello everyone!
Personally, I don’t support the idea of creating a carrier at 10.7 MHz (DDS or not), and upconverting it to 87.5-108 MHz.
To generate something at low frequency and then upconvert it to a higher frequency, is an ancient concept coming from the days where silicon chips did not exist, or they were unable to work satisfactory with high frequency outputs. Yes, engineers still do that today, but only in cases where they can’t do anything else.- Imagine if you have a 10.7 MHz FM carrier (risk=1), pass it through BPF (risk=2), use a low noise mixer (risk=3) with a stable (risk=4) and very clean VCO (risk=5), then use a VERY good 87.5-108 MHz BPF (risk=6) to get your FM band carrier. In this scenario, we have a chain of 6 points: if any of these gets malfunctioning, it will create a disaster at the output.
- Now imagine if you can create a clean carrier directly at 87.5-108 MHz (risk=1), and passing it through a LPF (risk=2). In this scenario, we have only 2 points of possible failure, and get the same -or even better- result on air.
So, why do the "10.7 MHz + upconversion"? Too much complexity, increased risk of getting a disaster, while you CAN have clean signal directly.
Concluding, I see no benefit and have to disagree with "PCI card with DDS 10.7 MHz".
I would preffer a "PCI card with DDS 87.5-108 MHz" and actually this IS my next project, for somebody here. 😉[quote author=”yorkie98″]@ Sigmacom, I would most certainly be interested in trying out a prototype I would be able to use it in a real environment and report the results. What kind of output power would your exciter generate?[/quote]
Yes yorkie98, that kind of prototype I have in mind, too! 🙂I have to redesign some things, because the "D-MPX" exciter you guys asked here, is a bit different from what I’ve already designed (*)!
This might take me a few days, so please wait a bit!(*) The first prototype is a 3U 19" rackmounted chassis, with modular design (see some pics of modules I’ve posted earlier).
The "AES/EBU card" can be exchanged with "analog audio L/R card", or 2 Mbit/s (E1) card. The "modulator card" can be exchanged with "DAB modulator card". The 30W RF card goes up to 500 MHz, so it needs replacement only for DAB @ L-Band.
In a few words, it has been designed to offer flexible configuration.Leif, may I help on that:
Suppose you want to create DDS + FM modulation in 87.5-108MHz band. So, if…a) You have a fast DDS, able to produce 108 MHz sine output, then you have "Direct-to-channel" exciter.
Nautel’s M50, IS "Direct-to-channel", mine IS "Direct-to-channel".b) You don’t have a fast one, you do DDS at a lower frequency and then upconvert it to 87.5-108MHz by using extra analog RF circuitry (VCO+PLL+Mixers+BPF, or multiplication, or whatever).
This is like RVR’s concept, and it is NOT considered as "Direct-to-channel" exciter.Did this helped? 🙂
Yes, I am from and live in Greece – Thessaloniki. 🙂
After this DDS, I can’t suggest any other exciter about linear frequency response…
Hi Sparky!
About the xtals in my previous post, I didn’t mean to modulate the xtal osc, but to use it instead of VCO+PLL LO.
I don’t know what loop filter they have in their (RVR DDS exciter) PLL LO, but they could avoid all that upconversion chain (DDS 8 MHz –> IF 70 MHz –> Final 87.5-108 MHz)
Either by multiplication or by using an ADI DDS (as you said), or an FPGA with TxDAC, or, or, or…I believe you agree with that! 🙂
