howto:hambasics:sections:practice
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howto:hambasics:sections:practice [2020/10/24 16:46] – [Selectivity] va7fi | howto:hambasics:sections:practice [2020/10/24 16:59] – va7fi | ||
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==== Filters ==== | ==== Filters ==== | ||
Sometimes a specific noise or interference is mixed in the signal and we'd like to reduce or eliminate it. One way is to use filters. | Sometimes a specific noise or interference is mixed in the signal and we'd like to reduce or eliminate it. One way is to use filters. | ||
- | * A filter that lets high frequencies through but blocks low frequencies is called a high pass filter. | + | * A filter that lets high frequencies through but blocks low frequencies is called a //high pass// filter. |
- | * A filter that lets low frequencies through but blocks high frequencies is called a low pass filter. | + | * A filter that lets low frequencies through but blocks high frequencies is called a //low pass// filter. |
- | * A filter | + | * Combining a high pass and low pass filter |
+ | * The " | ||
{{ notch1a.png }} | {{ notch1a.png }} | ||
Line 58: | Line 59: | ||
- The frequency is 7.100 MHz on LSB. | - The frequency is 7.100 MHz on LSB. | ||
- The scope shows this frequency relative to the entire band (7.000 Mhz to 7.300 Mhz) | - The scope shows this frequency relative to the entire band (7.000 Mhz to 7.300 Mhz) | ||
- | - At the bottom is the audio spectrum of what we can here (300 Hz to 2.5 kHz) | + | - At the bottom is the audio spectrum of what we hear (with a 2.4 kHz band pass filter). |
- | You'll notice that there' | + | You'll notice that there' |
<WRAP centeralign> | <WRAP centeralign> |
howto/hambasics/sections/practice.txt · Last modified: 2020/12/30 09:08 by va7fi