Questions tagged [radio]

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What is DAB modulation in signal generators?

I am using R&S signal generator and for generating a DAB signal there is an option for mentioning the modulation level in %. For example, we can generate DAB modulation 50% . I can understand that ...
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47 views

How to setup filters to catch 4FSK deviations

I'm trying to demodulate a radio signal from Motorol DP4801 (MOTOTRBO) that follows DMR specification. I'm receiving the signal by using HackRF with the rate sample 1 MHz. The radio uses frequency ...
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34 views

Help in identifying low speed image transmission protocol over RF

In the seventies I worked for Muirhead on press fax machines that used to transmit pictures over radio and landline as I recall two FM systems were used a carrier 800 Hz modulated +- 150 Hz and 1900Hz ...
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139 views

What kind of signal modulation is more resistant to jamming?

I've understood that spread-spectrum type of modulations are more resistant to narrow band jamming, for obvious reasons. What is less obvious is why someone would try to jam for example a cellular ...
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51 views

Considerations when determining squelch

I asked this question recently. From the comments I learned that squelch is not a hard and fast thing, and that many considerations might go into determining a reasonable value, depending on use, the ...
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19 views

Techniques use for pulsar observation and data reduction

I am new to radio astronomy field i am looking for help and guides about some basic technique used to search the pulsar and how to reduce the data capacity.
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2answers
34 views

What do you mean by radio sensing a channel?

I am slowly getting into the field of wireless communications, in particular with WiFi based communications. 802.11 MAC mentions that A station wishing to transmit first listens to the medium ...
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25 views

Will LoRa work from Earth to the Stratosphere

I'm unsure if this is the most suitable exchange however I thought it seemed most fitting personally, please correct me if I'm wrong. (I got redirected to here from the Network Engineering Exchange). ...
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91 views

Why do IQ Impairements, Quadrature Skew and DC offset have these geometric effects on the constellation?

I'm studying telecommunications, and would like to be sure to understand the maths behind these effects. For IQ Imbalance and DC offset, it seems pretty clear why we observe a rectangle shape or a ...
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2answers
85 views

how to eliminate interference in the same center frequency

I'm trying to receive an ASK signal in the 433 MHz center frequency with a bandwidth of 100KHz. I'm using a CC1101 transceiver connected to a Raspberry Pi GPIO ports. However, there is an intermittent ...
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1answer
59 views

how to guess what the interference source it could be

At work, we are in an industrial area, and there is always a signal that I receive inside my office which interferences with my tests. This signal is in the 433 MHz and when I see the spectrum, ...
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73 views

Coming up with a squelch value

I am building a scanning-type system. I have samples in $\textrm{dB}$ and I want to determine when to allow them through. I am trying to decide between allowing them through when they reach a ...
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34 views

Car engine audible through AM radio — what is this called?

A car's engine rotates in the range of 500 RPM to 6000 RPM. This is in the audible range. The car's engine is activated using spark plugs which are an electrical system at the same frequency (or some ...
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1answer
40 views

Output eqaution of a repeater?

Assume we have a signal repeater, a simple repeater that amplifies the signal then transmits it as is. Does the output power of the repeater is dependent on the received signal at the repeater ? for ...