For AY/YM, is there a limitation on the frequency of the output signal?
ZXNet echo conference «hardware.zx»
Hello, lvd
lvd> And yet, show me a diagram of how to exit the AUK! And at the same time an oscilloscope
lvd> Ask someone for a normal one, have a look...
ehhh I'll have to look into the diagram ;)
I'll take a look...
But I don’t know how to hold an oscilloscope in my hands ;)
Hello,GriV
Gri> however, I still made a datagram of the work
Gri> Here it is attached in the archive, I specially wrote a program that
Gri> would display volume levels - from 0 to 15 - running sequentially
Gri> values - and forming the corresponding levels on the DAC. (manager
Gri> register number 7 disabled = #FF; I tried changing other registers
Gri> the picture is consistently the same - every time)
Gri> Recorded on SB Live! 5.1 - maybe this unit itself is causing interference
Gri> but here's a fact - after the value "15" the transition to the value "0"
Gri> is accompanied by terrible fluctuations - even before the start
Gri> transition (jitter inside sounds?). Small values too
Gri> are accompanied by fluctuations (again visible from the graph) -
Gri> and the fluctuations in values themselves occur in the middle already
Gri> of the set value.
Gri>
Gri> In general, I cannot explain this rationally (there is only one sensory
Gri> filling the situation is some kind of nonsense :D), because the lengthGri> fluctuations corresponds to a frequency of about 8 kHz (quantization
Gri> of the given signal travels at a frequency of 48 kHz, occupies the same
Gri> fluctuation of about 6 measurements). Maybe it's the containers that
Gri> are at the AY output?
Gri>
And yet, show me a diagram of how the exit from the AUK is made! And at the same time the oscilloscope
Ask someone for a normal one, look at them...
Hello,GriV
Gri> ehhh I'll have to look into the diagram ;)
Gri> I'll take a look...
Gri> But I don’t know how to hold an oscilloscope in my hands ;)
Then let the owner hold it in his hands. And he turns his hands =)
Hello,GriV
ZY The length of the wire was 14 meters, maybe it was actually the influence of the echo.... I
I'll try to do it with a shorter wire....
Hello,GriV
Z.Y.Y. for each sample of the 48 kHz signal there was one re-oscillation,
a total of about 21 μs for the duration of one reflection (if considered as
option that the interference is caused by a reflected wave). 21 µs related to speed
wave travel through the cable (= speed of light in vacuum ;)) - will be about 6.5 km
the wave must run from here to there, i.e. the cable must be 3.25 km long.
It seems my cable is a little shorter ;)))))
Hello,GriV
Gri> which was digitalized. One last option seems unlikely to me
Gri> - well, it can’t be that the manufacturer released such a destructive one
Gri> product - which can normally record in this mode and at the same time
Gri> produce such terrible interference.
Gri>
This is not the manufacturer, but a drunken Chinese in the basement. ;)
> Only AY (I actually have YM) can blame.
>
By the way, poke the potato directly at the outputs of the AU, to the summary. Definitely normal there
signal (checked with an oscilloscope at home).
Hello,GriV
Gri> crappy output signal? Kwak so???
In the sense that then there will be no doubt that this is exactly the sound you have. =)
Press RESET immediately, Valery Grigoriev!
On Fri, 11 Nov 05 21:18:21 +0300, Valery Grigoriev wrote:
VG> option that interference is caused by a reflected wave). 21 μs related to
VG> speed of wave propagation through the cable (= speed of light in a vacuum ;)) -
VG> the wave will have to travel about 6.5 km back and forth, i.e. the cable should
VG> have a length of 3.25 km. It seems my cable is a little shorter ;)))))
1. Less than the speed of light.
2. It has nothing to do with the cable length.
Hello,GriV
Gri> That is why the limit for 10MBit Ethernet is 2.5 km
Gri> wires - to reliably detect interference and reflected waves.
Gri>
That's not why. This is an arbitrary length related to the timeout
collisions since the end of packet transmission. Those. this time is such that in it
with 2.5 km it is guaranteed that another transmitter will have time to arrive if it has started something
transmit. If you do more, there will be moments when there was a collision, but
the transmitter did not know about this -> it will consider the packet transmitted, but it is in some
points may not be accepted (deteriorated due to a collision). The result will be
coma
In reality, attenuation and distortion of the signal via the cable also plays a role.
Hello,GriV
Gri> I know that there is such a glitch, but I don’t understand what YM and the conclusion have to do with it
Gri> into its DACs, here we are not talking about the sound coming out (well, we mean
Gri> digitization output of course) either faster or slower, such nuances as
Gri> I took into account rounding to an even beat, we are talking about what appears
Gri> exactly wheezing, I don’t know what else to call it, in general it’s the same sound
Gri> however, it seems as if there is some kind of wheezing on top of it.
Gri>
Isn't your Scorpio green-turbo? He accelerates on the curb.
Hello, GriV
┌─- code ───
LD A,(HL) ; 7t.
AND 15 ; 7t.
LD D,A ; 4t.
LD A,(HL) ; 7t.
AND #F0 ; 7t.
LABEL1:OUT (C),D
(WHERE?)
SUB #10 ; 7t.
JR NZ LABEL1 ; 13t, like, don't remember anymore
INC. HL ; 6t.
└── code ───
And now count the beats in different cases.
Hello fk0
fk0> Isn’t your Scorpio green-turbo? He accelerates on the curb.
Scorpio is yellow, it does not accelerate, the problem is not in the scorpion but in the sound...
Hello, lvd
lvd> That's not why. This is an arbitrary length associated with time
lvd> wait for a collision from the moment the packet is transmitted. Those. it's time
lvd> such that another transmitter is guaranteed to reach it from 2.5 km
lvd> come if he started transmitting something. If you do more, then
lvd> there will be moments when there was a collision, but the transmitter did not know about it ->
lvd> it will consider the packet to be transmitted, but at some points it may not be
lvd> is accepted (will be corrupted due to collision). The result will be coma.
lvd> In reality, weakening and distortion of the signal also plays a role
lvd> cable.
yeah, exactly with this - if the signal moved at, say, half the speed, then
I would have to make the ring not 2.5 km, but 1.25 ;)))
offtopic: Repeaters take care of attenuation and distortion - they can theoretically
It’s a good idea to set it, but the limitation is based on the speed of the signal.
If the signal passed through everything instantly, then why would there be no need for restrictions?
along the cable length - set up repeaters and period.