Likewise. Page 2 of NRSC-2 under "RF Maximum Occupied Bandwidth Specification". +/- 10 kHz deviation from carrier at 0 dB attenuation relative to carrier. 20 kHz total occupied bandwidth, 10 kHz audio bandwidth. Out-of-band attenuation table also included below.
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rdf,
Good point.
What about the measurement RBW rise times?
1kHz RBW risetime 350usec
300Hz RBW risetime 1,167usec
What kind of music notes, percussion, etc. will you get if you amplifier has such slow risetimes.
Well, all the quick dynamics of music will be severely attenuated.
Similar to listening to a 300Hz low pass filter.
OK, I will give you music through a 1kHz low pass filter.
You can even center the 1kHz anywhere you want, i.e. from 500Hz to 1500Hz.
That unfair measurement averages the music. But your ears do not work that slowly, they hear the music transients and decays unattenuated by narrow RBW filters.
Hi Fi?
Not like it used to be.
I got rid of my beautiful Eico AM tuner. It had a Wide/Narrow IF bandwidth switch, and the deep 10kHz audio notch filter to cut out the adjacent channels
stations carrier beat tones (yes, plural adjacent channels and adjacent carriers beat tones).
But legislators and regulators had to make all those modern improvements to AM, in order to justify their jobs, and to create new jobs for the manufacturers of new transmitter exciters, new radios, etc.
Why destroy what used to be a really fine thing.
Good point.
What about the measurement RBW rise times?
1kHz RBW risetime 350usec
300Hz RBW risetime 1,167usec
What kind of music notes, percussion, etc. will you get if you amplifier has such slow risetimes.
Well, all the quick dynamics of music will be severely attenuated.
Similar to listening to a 300Hz low pass filter.
OK, I will give you music through a 1kHz low pass filter.
You can even center the 1kHz anywhere you want, i.e. from 500Hz to 1500Hz.
That unfair measurement averages the music. But your ears do not work that slowly, they hear the music transients and decays unattenuated by narrow RBW filters.
Hi Fi?
Not like it used to be.
I got rid of my beautiful Eico AM tuner. It had a Wide/Narrow IF bandwidth switch, and the deep 10kHz audio notch filter to cut out the adjacent channels
stations carrier beat tones (yes, plural adjacent channels and adjacent carriers beat tones).
But legislators and regulators had to make all those modern improvements to AM, in order to justify their jobs, and to create new jobs for the manufacturers of new transmitter exciters, new radios, etc.
Why destroy what used to be a really fine thing.
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The smaller the resolution bandwidth, the better the spectrum analyser output will resolve details in the frequency domain, but the longer it will take until each frequency sweep is finished. The only relevance to the audio is that you can't actually go above 9.8 kHz or so audio bandwidth, because the measurement at 10 kHz offset frequency from the carrier will be done with a bandpass filter that goes from 9.85 kHz to 10.15 kHz offset frequency.
MarcelvdG,
I worked as a spectrum analyzer specialist in manufacturing, engineering, marketing, training, and product support (and earlier for the US Government too).
You are missing one very important point about what a narrow RBW does to transient spectral events. Yes, Including musical transient events.
The rise time of an RBW causes a spectral event to appear with a much lower amplitude than it actually is.
Tune your spectrum analyzer to 2.5kHz offset from the carrier. Set the RBW to 300Hz. Set the analyzer to zero span.
Now, turn on max hold, and observe the amplitude of the spectrum at the 3.5kHz offset from the carrier, with the large amplitude attenuation due to the rise time of the 300Hz RBW.
Then, turn on the 1kHz RBW, and notice that the musical transients are much larger in amplitude.
Yes, of course the 1kHz RBW captures more energy; but run the tests below an you will see (and understand)
I would use an RF signal generator with music applied.
You can repeat this kind of test (if you are lucky to have such equipment).
Try it with the first 30 seconds of a Jazz CD that has drum shots, cymbals, etc.
First with a 300Hz RBW, then repeat the test with a 1kHz RBW.
But for an easier to understand proof, set a second signal generator (AFG or ARB) for a single cycle of 2.5kHz sine wave.
Apply that to the input of an RF signal generator.
Try again with the 300Hz RBW, and then with the 1kHz RBW. The impulse amplitude will be different by approximately 20 Log (300Hz/1000Hz).
Then watch music, with the transient decay of a number of drums, etc. That kind of instrument has a sine wave with a natural exponential decay rate.
Generate an ARB waveform to duplicate that impulse, and repeat the 300Hz and 1kHz tests.
(RBWs are rated by both there continuous bandwidth, and also by their Impulse bandwidth)
I not only supported traditional analog spectrum analyzers, I supported real time analyzers that also had real time color spectrograms.
But you probably will not even see a real time analyzer, and even less likely be able to operate them.
For anybody that has access to such test equipment, . . . have fun trying these tests out.
I worked as a spectrum analyzer specialist in manufacturing, engineering, marketing, training, and product support (and earlier for the US Government too).
You are missing one very important point about what a narrow RBW does to transient spectral events. Yes, Including musical transient events.
The rise time of an RBW causes a spectral event to appear with a much lower amplitude than it actually is.
Tune your spectrum analyzer to 2.5kHz offset from the carrier. Set the RBW to 300Hz. Set the analyzer to zero span.
Now, turn on max hold, and observe the amplitude of the spectrum at the 3.5kHz offset from the carrier, with the large amplitude attenuation due to the rise time of the 300Hz RBW.
Then, turn on the 1kHz RBW, and notice that the musical transients are much larger in amplitude.
Yes, of course the 1kHz RBW captures more energy; but run the tests below an you will see (and understand)
I would use an RF signal generator with music applied.
You can repeat this kind of test (if you are lucky to have such equipment).
Try it with the first 30 seconds of a Jazz CD that has drum shots, cymbals, etc.
First with a 300Hz RBW, then repeat the test with a 1kHz RBW.
But for an easier to understand proof, set a second signal generator (AFG or ARB) for a single cycle of 2.5kHz sine wave.
Apply that to the input of an RF signal generator.
Try again with the 300Hz RBW, and then with the 1kHz RBW. The impulse amplitude will be different by approximately 20 Log (300Hz/1000Hz).
Then watch music, with the transient decay of a number of drums, etc. That kind of instrument has a sine wave with a natural exponential decay rate.
Generate an ARB waveform to duplicate that impulse, and repeat the 300Hz and 1kHz tests.
(RBWs are rated by both there continuous bandwidth, and also by their Impulse bandwidth)
I not only supported traditional analog spectrum analyzers, I supported real time analyzers that also had real time color spectrograms.
But you probably will not even see a real time analyzer, and even less likely be able to operate them.
For anybody that has access to such test equipment, . . . have fun trying these tests out.
MarcelvdG,
I am glad you asked, Thank You!
For those who never listened to pristine clear channel AM audio, and can not remember it, it does not matter.
Suppose you have a very good clear channel capable AM tuner, and want to hear the wideband audio of a traditional clear channel station.
Unfortunately, the adjacent station is broadcasting sidebands of voice and music that [badly] interferes with your enjoyment of the clear channel stations audio channel that you are listening to.
Even the control of the adjacent stations night time directional antennas, and night time power management can not always overcome when the skip is working.
In that case, the adjacent channel interference will be heard along with the clear channel station's audio.
Regulations can make things better (sometimes, but not always).
Another example of government regulations:
All the devices in your house have to pass government dictated EMI regulations (Electro Magnetic Interference).
But that does not mean they are EMC (Electro Magnetic[ally] Compatible). Instead, even if they pass EMI regulations, they can interfere with each other.
I am glad you asked, Thank You!
For those who never listened to pristine clear channel AM audio, and can not remember it, it does not matter.
Suppose you have a very good clear channel capable AM tuner, and want to hear the wideband audio of a traditional clear channel station.
Unfortunately, the adjacent station is broadcasting sidebands of voice and music that [badly] interferes with your enjoyment of the clear channel stations audio channel that you are listening to.
Even the control of the adjacent stations night time directional antennas, and night time power management can not always overcome when the skip is working.
In that case, the adjacent channel interference will be heard along with the clear channel station's audio.
Regulations can make things better (sometimes, but not always).
Another example of government regulations:
All the devices in your house have to pass government dictated EMI regulations (Electro Magnetic Interference).
But that does not mean they are EMC (Electro Magnetic[ally] Compatible). Instead, even if they pass EMI regulations, they can interfere with each other.
I'm not even fully convinced Redbook CD is peak Hi Fi and would never suggest it of AM. From long experience with instrumentation grade receivers though the basic protocol is capable of unrecognizably better listening than decades of the lowest of low bar consumer products and programmer's "tastes" could begin to hint. Many would be shocked.
As you note the RF side is challenging but regulation is the only reason the system works at all. First adjacent stations are normally distantly spaced, for example 670 Chicago, 680 Toronto and 690 Montreal. Occasionally skywave overcomes distance and becomes a problem but it's usually temporary and driven by atmospherics. The fun starts where regulation stops, for example the lack of a skywave agreement between the US and Canada.
As you note the RF side is challenging but regulation is the only reason the system works at all. First adjacent stations are normally distantly spaced, for example 670 Chicago, 680 Toronto and 690 Montreal. Occasionally skywave overcomes distance and becomes a problem but it's usually temporary and driven by atmospherics. The fun starts where regulation stops, for example the lack of a skywave agreement between the US and Canada.
Skywave late night ~1000 toronto IMHO is the only AM worth listening to in the desolate US western plains. St.Louis west to at least Utah.
5000 hz AM was okay, IMHO. Clear channel KRLD & WLS were even better, when the Cubans weren't misbehaving. I didn't get speakers better than that until I was 20, (1970) and I was a hifi nut. People played pop 45s on those dreadful players with the 5 gram ceramic cartridges, that wiped out all the highs on the PVC in 1 play. So the records sounded just like the radio! No nasty highs! I found out how damaging Mothers RCA stereo was after a new needle didn't stop the damage in 1968. I was a classical nut, too.
But we're not getting 5000 hz AM. AM is all compressed within an inch of its life, what 4 or 5 "music" AM stations there are anymore. The two daytime AM "music" stations in my town now play urban poetry, not music. The rest of AM is blah, blah, blah, blah. including WHAS-AM84, that used to have such wonderful pop music late at night. I listened to WHAS in Houston, sometimes. I wonder if even us nuts banded together & bought 3 clear channel stations, if pure mono clear channel skywave could be returned to the air with modern regulations. Probably we are supposed to tap Sirius satellite radio into an artery via credit card, if we want to listen to music between towns. In the high plains, I'm going to get country "music", high school sports, or hog reports, AM or FM either one. I'm probably going to break down & buy a smart phone, since dickies has started making cargo pants out of polyester that will protect my knees in a fall off a bicycle. (All others brands are cotton, burn right through on pavement)(Up to now I use a stupid phone that fits in a pants pocket in case of falls).(I only drive cars on annual vacations).
5000 hz AM was okay, IMHO. Clear channel KRLD & WLS were even better, when the Cubans weren't misbehaving. I didn't get speakers better than that until I was 20, (1970) and I was a hifi nut. People played pop 45s on those dreadful players with the 5 gram ceramic cartridges, that wiped out all the highs on the PVC in 1 play. So the records sounded just like the radio! No nasty highs! I found out how damaging Mothers RCA stereo was after a new needle didn't stop the damage in 1968. I was a classical nut, too.
But we're not getting 5000 hz AM. AM is all compressed within an inch of its life, what 4 or 5 "music" AM stations there are anymore. The two daytime AM "music" stations in my town now play urban poetry, not music. The rest of AM is blah, blah, blah, blah. including WHAS-AM84, that used to have such wonderful pop music late at night. I listened to WHAS in Houston, sometimes. I wonder if even us nuts banded together & bought 3 clear channel stations, if pure mono clear channel skywave could be returned to the air with modern regulations. Probably we are supposed to tap Sirius satellite radio into an artery via credit card, if we want to listen to music between towns. In the high plains, I'm going to get country "music", high school sports, or hog reports, AM or FM either one. I'm probably going to break down & buy a smart phone, since dickies has started making cargo pants out of polyester that will protect my knees in a fall off a bicycle. (All others brands are cotton, burn right through on pavement)(Up to now I use a stupid phone that fits in a pants pocket in case of falls).(I only drive cars on annual vacations).
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The reproduction of recorded music, as well as live music radio broadcasts generally made improvements as the decades rolled on and on.
AM was the start, then Mono FM.
I remember my dad's separate optional FM tuner in his 1947 Magnavox. In the mid 50s and early 60s, a local station broadcast both AM and FM mono.
Occasionally the AM and FM was simulcast for music programs. There was even an AM IF bandwidth switch.
The FM broadcast was so very much better from the same music source than from the simulcast AM, whether live or recorded. No surprise here.
Some other station's clear channel broadcasts were very good too.
After 78s, along came 45s and 33 LPs; then LP stereo. Some got Stereo Tape recorders, and prerecorded 7-1/2 inch tapes.
The key was to enjoy the music, with the system you had at the time.
There were some improvements (3 steps forward, 2 steps back)
Stereo FM reduced the signal to noise, and had more Harm. and IM distortion, and also multi-path.
I never cared for 8 track, and did not like 1/8 inch cassette tapes.
CDs took off.
Then along came some early horrible MP3s, at a 15k sample rate, with brick wall fall-off at 7.5kHz.
I remember when Borders had listening stations, with CD players that had 5 or 6 CDs on the turret; the earphone output was connected to headphones. You could actually determine whether or not you wanted to purchase a CD from the sound of those players. You could play all the tracks of all 5 or 6 CDs, and then move on to the next multi-disk CD player.
Then, all those players were ripped out of the listening stations. They put in some form of streaming music; it was a terribly Regurgitated recording of just a few tracks per CD, and it only had short portions of those tracks.
When I say Regurgitated recordings, I mean that it was an order of magnitude worse than the early 15k / 7.5k MP3.
It sounded like a phaser phlanger operating between left and right channel, that almost made you twist your head and neck trying to follow that sound.
I never purchased any CD from those 'new and improved' listening stations.
Shortly after that, Borders went out of business.
My 'new' major city location has such terrible FM reception, both in stereo, and even with the tuner set to mono. I confirmed the problems with an FFT. It was so bad, you do not need ears to know there are major problems.
Then I checked the same Jazz and Classical 'stations' by streaming, and the sound was so much better, and also has a much improved FFT.
When it comes to Skip, we had a 5kW AM station in a small town, and one day the station got a letter from a listener in Australia, who enjoyed listening to the Oregon station.
Another skip time: There was a Very large visible sunspot (do not try this, the sun was very low in the extremely smoky late afternoon sky).
A 6 food bow-tie antenna was connected to the old black and white TV.
Channel 2, Denver Colorado came through all the way to Southwest Oregon.
AM was the start, then Mono FM.
I remember my dad's separate optional FM tuner in his 1947 Magnavox. In the mid 50s and early 60s, a local station broadcast both AM and FM mono.
Occasionally the AM and FM was simulcast for music programs. There was even an AM IF bandwidth switch.
The FM broadcast was so very much better from the same music source than from the simulcast AM, whether live or recorded. No surprise here.
Some other station's clear channel broadcasts were very good too.
After 78s, along came 45s and 33 LPs; then LP stereo. Some got Stereo Tape recorders, and prerecorded 7-1/2 inch tapes.
The key was to enjoy the music, with the system you had at the time.
There were some improvements (3 steps forward, 2 steps back)
Stereo FM reduced the signal to noise, and had more Harm. and IM distortion, and also multi-path.
I never cared for 8 track, and did not like 1/8 inch cassette tapes.
CDs took off.
Then along came some early horrible MP3s, at a 15k sample rate, with brick wall fall-off at 7.5kHz.
I remember when Borders had listening stations, with CD players that had 5 or 6 CDs on the turret; the earphone output was connected to headphones. You could actually determine whether or not you wanted to purchase a CD from the sound of those players. You could play all the tracks of all 5 or 6 CDs, and then move on to the next multi-disk CD player.
Then, all those players were ripped out of the listening stations. They put in some form of streaming music; it was a terribly Regurgitated recording of just a few tracks per CD, and it only had short portions of those tracks.
When I say Regurgitated recordings, I mean that it was an order of magnitude worse than the early 15k / 7.5k MP3.
It sounded like a phaser phlanger operating between left and right channel, that almost made you twist your head and neck trying to follow that sound.
I never purchased any CD from those 'new and improved' listening stations.
Shortly after that, Borders went out of business.
My 'new' major city location has such terrible FM reception, both in stereo, and even with the tuner set to mono. I confirmed the problems with an FFT. It was so bad, you do not need ears to know there are major problems.
Then I checked the same Jazz and Classical 'stations' by streaming, and the sound was so much better, and also has a much improved FFT.
When it comes to Skip, we had a 5kW AM station in a small town, and one day the station got a letter from a listener in Australia, who enjoyed listening to the Oregon station.
Another skip time: There was a Very large visible sunspot (do not try this, the sun was very low in the extremely smoky late afternoon sky).
A 6 food bow-tie antenna was connected to the old black and white TV.
Channel 2, Denver Colorado came through all the way to Southwest Oregon.
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This is mine old design a pll for 80 to 140 Mhz with switches. resolution with switches was high.
It was one of the best, did had feedback also to the varacter, so did demodulate and feed back, getting very wide stereo separation.
and a sound who was beautifull and dead quit no noise from pll.
It is years ago though, now it is punisable with high fines.
AM is atractive for dab, with good compression of audio it will work.
So I was a pirate in these days. The pcb I did made in ultiboard, still have the dos version, so old is this design, still working???
It was one of the best, did had feedback also to the varacter, so did demodulate and feed back, getting very wide stereo separation.
and a sound who was beautifull and dead quit no noise from pll.
It is years ago though, now it is punisable with high fines.
AM is atractive for dab, with good compression of audio it will work.
So I was a pirate in these days. The pcb I did made in ultiboard, still have the dos version, so old is this design, still working???
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As a kid I had a "Dick Smith" book with a collection of electronic circuits with things like buzzers, door bells and AM & FM radios, and I remember being able to make low-powered broadcasts (<0.5W iirc) for fun.
As far as I'm concerned, the ability of people to do that is a matter of cultural heritage, and definitely something that must be passed on so it's not forgotten. It's bad enough that almost nobody has the faintest idea how to make analogue recordings that don't rely on magic ingredients in case they suddenly become unobtainium (like high quality magnetic tape).
As far as I'm concerned, the ability of people to do that is a matter of cultural heritage, and definitely something that must be passed on so it's not forgotten. It's bad enough that almost nobody has the faintest idea how to make analogue recordings that don't rely on magic ingredients in case they suddenly become unobtainium (like high quality magnetic tape).