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PostPosted: Mon Sep 24, 2018 3:38 pm 

Joined: Sun Sep 23, 2018 6:03 pm
Posts: 3
Recently I'm trying to use DRMAX to TX analog AM Stereo Signal. It's undoubtedly feasible and good-sounding by using HDSDR combined with Stereo Tool but complicated. Such complication would be unnecessary and hugely simplified if Stereo Tool could make a pure carrier signal. As so, I hand in my wish list to you about adding the function of generating AM Stereo carrier signal under the "AM Transmitter" tab.

Since so, I also hope AM SSB, FM function could be added and unlocked by paying a reasonable cost.


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PostPosted: Wed Sep 26, 2018 6:49 pm 

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 41
Quote:
Recently I'm trying to use DRMAX to TX analog AM Stereo Signal. It's undoubtedly feasible and good-sounding by using HDSDR combined with Stereo Tool but complicated. Such complication would be unnecessary and hugely simplified if Stereo Tool could make a pure carrier signal. As so, I hand in my wish list to you about adding the function of generating AM Stereo carrier signal under the "AM Transmitter" tab.

Since so, I also hope AM SSB, FM function could be added and unlocked by paying a reasonable cost.
you mean something similar like a 25Hz pilot tone for C-QUAM AM Stereo ?
as it is now, i have to generate my own 25Hz pilot tone for C-QUAM outside of using ST so the tone does not affect ST processing.


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PostPosted: Fri Sep 28, 2018 7:10 pm 

Joined: Sun Sep 23, 2018 6:03 pm
Posts: 3
Quote:
you mean something similar like a 25Hz pilot tone for C-QUAM AM Stereo ?
as it is now, i have to generate my own 25Hz pilot tone for C-QUAM outside of using ST so the tone does not affect ST processing.
Hello! Glad to have your reply. I didn't mean to add the function of "Pilot Tone". Let me describe it more, shall I?
First of all, forget about AM stereo and think of a normal mono AM transmitter instead. Nonetheless, the difference is that such transmitter doesn't generate carrier signal (similar to SSB). Thus, an AM receiver cannot demodulate the sound correctly, but you can use a receiver capable of demodulating SSB signal to hear clear sound. So, theoretically, we need to supplement a virtual 0 Hz carrier signal for the transmitter.
0 Hz signal cannot be generated by any software and soundcard. If we suppose that Stereo Tool (ST) could fully functional in generating the carrier signal, we could at least generate any carrier signal above 1 Hz, say +5 kHz. Accordingly, we could shift down the intermediate frequency (IF) by 5 kHz. As long as ST also shift all the input (voice signal) up by 5 kHz, we could hear the voice through normal AM radio.
Here, there might be another problem occur: a pair of symmetric signals appear simultaneously mirroring around the IF. So ST should suppress the mirror signal in order to obtain the purely true AM signal.
Hope that my lengthy explanation can make some help.


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PostPosted: Tue Oct 02, 2018 10:32 pm 

Joined: Wed Nov 08, 2017 3:16 pm
Posts: 41
Quote:
Quote:
you mean something similar like a 25Hz pilot tone for C-QUAM AM Stereo ?
as it is now, i have to generate my own 25Hz pilot tone for C-QUAM outside of using ST so the tone does not affect ST processing.
Hello! Glad to have your reply. I didn't mean to add the function of "Pilot Tone". Let me describe it more, shall I?
First of all, forget about AM stereo and think of a normal mono AM transmitter instead. Nonetheless, the difference is that such transmitter doesn't generate carrier signal (similar to SSB). Thus, an AM receiver cannot demodulate the sound correctly, but you can use a receiver capable of demodulating SSB signal to hear clear sound. So, theoretically, we need to supplement a virtual 0 Hz carrier signal for the transmitter.
0 Hz signal cannot be generated by any software and soundcard. If we suppose that Stereo Tool (ST) could fully functional in generating the carrier signal, we could at least generate any carrier signal above 1 Hz, say +5 kHz. Accordingly, we could shift down the intermediate frequency (IF) by 5 kHz. As long as ST also shift all the input (voice signal) up by 5 kHz, we could hear the voice through normal AM radio.
Here, there might be another problem occur: a pair of symmetric signals appear simultaneously mirroring around the IF. So ST should suppress the mirror signal in order to obtain the purely true AM signal.
Hope that my lengthy explanation can make some help.
i think i understand what you are saying but i dont believe ST is capable of such measures for that specific intention.
that would require a complete overhaul of ST to provide "right/left" SB IF's from the center frequency and a specific and special type of soundcard that could generate +/- DC and/or carrier frequency that needs AM modulation (i think this is what you mean, the similar theory of left channel on the LSB of the IF and the right channel on the USB of the IF)
i have an idea what you are talking about as this is something i have done before to generate a "different" measure of AM stereo by attempting to modulate the AM-LSB for the left channel and the AM-USB for the for the right channel however, this is extremely difficult to make work even hardware wise.


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PostPosted: Thu Jan 31, 2019 12:08 am 
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Joined: Mon Mar 17, 2008 1:40 am
Posts: 9893
I don't really understand what you're saying. I know it can be done with SDR, but what kind of signal could Stereo Tool generate that - when broadcast with an AM transmitter - would be demodulated as a stereo signal.

Maybe I should ask you differently: Can you generate a signal with a sound card that when sent through an AM transmitter triggers a receiver to detect a stereo broadcast? The way I understood it you need 2 carriers in quadrature (which kinda would cause something like L and R on different side bands I assume). But, can you configure a normal AM transmitter to broadcast a signal as SSB? If not, whatever goes onto the air will be symmetrical, hence mono.


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