PL tone removal?
$begingroup$
How are PL tones (CTSS, et.al.) typically removed from the audio of received VHF FM repeater signals?
Is it done with a fixed high-pass filter? Or a notch, when using a transceiver with the PL tone configured correctly? Or dynamically, by assuming any constant low tone detected is hum to be removed by an auto-adaptive notch?
Or is it sometimes not removed by filtering because the tiny speakers on handheld receivers don't have sufficient low frequency response?
tone-squelch
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
$endgroup$
add a comment |
$begingroup$
How are PL tones (CTSS, et.al.) typically removed from the audio of received VHF FM repeater signals?
Is it done with a fixed high-pass filter? Or a notch, when using a transceiver with the PL tone configured correctly? Or dynamically, by assuming any constant low tone detected is hum to be removed by an auto-adaptive notch?
Or is it sometimes not removed by filtering because the tiny speakers on handheld receivers don't have sufficient low frequency response?
tone-squelch
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
$endgroup$
add a comment |
$begingroup$
How are PL tones (CTSS, et.al.) typically removed from the audio of received VHF FM repeater signals?
Is it done with a fixed high-pass filter? Or a notch, when using a transceiver with the PL tone configured correctly? Or dynamically, by assuming any constant low tone detected is hum to be removed by an auto-adaptive notch?
Or is it sometimes not removed by filtering because the tiny speakers on handheld receivers don't have sufficient low frequency response?
tone-squelch
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
$endgroup$
How are PL tones (CTSS, et.al.) typically removed from the audio of received VHF FM repeater signals?
Is it done with a fixed high-pass filter? Or a notch, when using a transceiver with the PL tone configured correctly? Or dynamically, by assuming any constant low tone detected is hum to be removed by an auto-adaptive notch?
Or is it sometimes not removed by filtering because the tiny speakers on handheld receivers don't have sufficient low frequency response?
tone-squelch
tone-squelch
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
asked 11 hours ago
hotpaw2hotpaw2
3,17321733
3,17321733
add a comment |
add a comment |
1 Answer
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$begingroup$
I would expect some low-frequency roll-off in the amp and the speaker. You could check by putting headphones on the speaker output.
Wikipedia says that a 300 Hz cutoff high-pass filter is common.
https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Also, the CTSS tone is injected at a lower level than the voice content, usually 15% of full deviation. That is about 8 dB below full modulation.
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
$endgroup$
add a comment |
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1 Answer
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1 Answer
1
active
oldest
votes
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votes
$begingroup$
I would expect some low-frequency roll-off in the amp and the speaker. You could check by putting headphones on the speaker output.
Wikipedia says that a 300 Hz cutoff high-pass filter is common.
https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Also, the CTSS tone is injected at a lower level than the voice content, usually 15% of full deviation. That is about 8 dB below full modulation.
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
$endgroup$
add a comment |
$begingroup$
I would expect some low-frequency roll-off in the amp and the speaker. You could check by putting headphones on the speaker output.
Wikipedia says that a 300 Hz cutoff high-pass filter is common.
https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Also, the CTSS tone is injected at a lower level than the voice content, usually 15% of full deviation. That is about 8 dB below full modulation.
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
$endgroup$
add a comment |
$begingroup$
I would expect some low-frequency roll-off in the amp and the speaker. You could check by putting headphones on the speaker output.
Wikipedia says that a 300 Hz cutoff high-pass filter is common.
https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Also, the CTSS tone is injected at a lower level than the voice content, usually 15% of full deviation. That is about 8 dB below full modulation.
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
$endgroup$
I would expect some low-frequency roll-off in the amp and the speaker. You could check by putting headphones on the speaker output.
Wikipedia says that a 300 Hz cutoff high-pass filter is common.
https://en.wikipedia.org/wiki/Continuous_Tone-Coded_Squelch_System
Also, the CTSS tone is injected at a lower level than the voice content, usually 15% of full deviation. That is about 8 dB below full modulation.
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
answered 9 hours ago
Walter Underwood K6WRUWalter Underwood K6WRU
1,685712
1,685712
add a comment |
add a comment |
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