7

Not too sure if you will be able to find datasheet for specific cell phone. These are proprietary information and mobile phone manufactures usually don’t share this type of information in public for various reasons. Depending on the business needs you should contact the vendors directly and seek datasheet, which might be obtained under a non-disclosure ...


6

As you might have already realized there is a good reason that some of Bluetooth headset are inexpensive. Poor design. High quality, well designed Bluetooth headset tend to be expensive. Also not all expensive Bluetooth headsets are high quality. While it is difficult to root cause failures without physically analyzing the hardware, I will provide some ...


6

You can't ignore the difference between 2D and 3D in this situation. To a first approximation, all GPS satellites are located on the surface of a sphere. There is no way that any three points on a sphere can be colinear. There is one situation that can be ambiguous, and that's when N satellites are equidistant from the receiver. However, in this case, one ...


6

Reverse the logic for the RF tag detector and alarm. As you state, RF detectors and alarms activate when the RF tag is within range of the detector. Change the logic of the detector-alarm system to sound the alarm, as the default situation, when the tag is out of range. When the tag is in range the alarm turns off. It's a similar logic to that of dead man ...


5

This happens on a bit level of the receiver electronics. For every byte you have to receive 8 bits. At this point in communication you only decoded the signal (eg. converted the electrical power or voltage) levels to bits. You receive bits in the buffer. You are constantly filling the buffer (on a bit level), so you can check the buffer to see if you ...


5

For a LTE base station is it possible to determine the relationship between the signal strength and distance? Ideally yes. Practically, probably not very reliably. Given the following pieces of information and assumptions, you can find the distance between any transmitter and receiver: The transmitting antenna's radiation pattern and orientation (gain) ...


4

There are many factors that make BLE low power, and I have attempted to address as many of them as possible. In order to better understand the power consumption differences between Bluetooth classic and BLE, it would helpful to look at some of the differences between the Bluetooth technologies. This would help appreciate the difference in power consumption. ...


4

Firstly you seem to be under the common misunderstanding that the GPS satellites somehow calculate where a GPS receiver is. They don't. The satellites are transmit only systems (ignoring the command and control radio links with their control stations) and a GPS receiver is a receive only system. As user114749 indicated RFID is the closest to what you want ...


3

Different materials reflect, absorb, and scatter different wavelengths of light. The ionized layer at the edge of earth's atmosphere happens to reflect a certain range of wavelength while transmitting others. This is due to the physics of the material. The reason you can't use the atmosphere to reflect shorter wavelengths for the purposes of communication,...


3

how are three satellites sufficient to find a unique point in gps? They are not. It takes four satellites minimum. GPS needs to solve for the point in four dimensions, X, Y, Z and time. Four unknowns requires at least four inputs to solve. In the case of GPS these are the relative time offsets of the signals received at the coordinate in question.


3

You can see this information if you enter "field test mode". Google that for device specific instructions. It should show you the name or serial number of the base station you are connected to, but I'm not sure if you can use that to find it's physical location, although I haven't tried.


3

Wifi uses Orthogonal frequency-division multiplexing (OFDM). OFDM is resilient to delay spreading which essentially is multipath RF signals or signal bouncing off walls per your question. Here is better explanation from PHY Basics: How OFDM Subcarriers Work. An advantage of OFDM is that by using a reduced symbol rate of 250,000 symbols per second the ...


3

First, you should link in a reference to the Hata and Ericsson models. I haven't heard of them, and a quick search on Google didn't give anything. Path loss and received signal strength are typically calculated using the Friis Transmission Equation. http://en.wikipedia.org/wiki/Friis_transmission_equation To use this equation you must know the distance ...


3

The reason you can't find many modules around 100 MHz is that it's not an open frequency and you generally need a permit to transmit at those frequencies. Another reason is that you will face some serious interference from FM radio broadcasts that are all in this frequency region. I'm not sure what size you imagine your module being but at 100 MHz the ...


2

You asked too many questions in one, so I'll just briefly make a few key points. Think of the problem these devices have. The dynamic range of light levels they have to work with is enormous, and the actual signal can be small relative to the ambient light level. One way they deal with this is to high pass filter the received light level. That ...


2

The wave propagation speed is only relevant when you start approaching the theoretical limit of that type of wave's ability to transmit information. For an analogy, consider people having a conversation in a room full of air. They're using sound waves to transmit information. The speed at which those waves propagate is the same for every speaker, in that ...


2

Typically, the max is 100mW (20dBm). You can refer to an example wifi chip datasheet (This one is used in many mobile phones with Snapdragon processor) - https://developer.qualcomm.com/download/sd410/wcn3620-wireless-connectivity-ic-device-specification.pdf


2

There are a few factors at play. Firstly as Olin indicated the signal bandwidth and data rates are different. It is a fundamental rule of information theory that the maximum amount of data you can pass through a data channel depends upon the channel bandwidth and the signal to noise ratio. See the Shannon-Hartley theory for details. This means that if ...


2

Generally when you need to scale up a clock you use a PLL (Phase lock loop). A very crude explanation is that you have a voltage controlled oscillator at roughly the required frequency. You divide the output of this down to your reference frequency (a factor of 60 in this case) and then compare it to your reference clock input. The difference between the ...


2

They would be a great hazard to air traffic; The umbilical would be essentially invisible to passing aircraft. In spite of regulations not to fly here or there.


2

To be totally honest there is really only one technology you should be looking for. Infrared, all you need is a light transistor and a infrared led, thats it. Cheap as hell, well known, and robust works in wide range of situation and is not prone to noise. Anyway, You can also try radio waves and sound.


2

The operational frequency operational range of the proposed antenna is within the frequency range of the old antenna. It should not be an issue from frequency standpoint. If the gains are similar chances are that the replacement antenna might work. I also noticed the following statement for your alternative antenna. So the alternative antenna is not ...


2

Your understanding is correct. Here is an alternate definition from Wikipedia - Bandwidth Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies. It is typically measured in hertz, and depending on context, may specifically refer to passband bandwidth or baseband bandwidth. Alternate definition: The ...


1

Looking at if the device supports BLE 4.0, 4.1, 4.2 or 5.0 is a good start. Not all BLE modules are 5.0 capable. What type is distance range might be a parameter to consider some BLE module have line of sight range of 1km or more at a low data rates. Below is a short side by side comparison to help get started.


1

As with any physical equation, the units of a constant, in this case "spectrum efficiency," are chosen so that the final result is in the units desired. So, if you're going for an answer in dB, then somewhere in this equation you'll multiply this constant by time (s , seconds) and a bandwidth in Hz.


1

There are Bluetooth adapters available which will hook into audio system via 3mm jack or optical jack and broadcast the music to your headset. However if you want to receive the music into your phone, you need another adapter to hook into your phone audio jack. I have both and they cost me $20 each.


1

many radio receivers contain a circuit called an IF oscillator. the output of this oscillator is added to the radio frequency signal that the radio is receiving to downconvert the incoming high frequency to a lower frequency that is easier to process. Old radios used IF oscillators that were powerful enough to actually transmit signals on their IF frequency ...


1

The Mobile Network Code (MNC) is either a two digit ("European" standard) or three digit ("North American" standard) identifier, with in the Mobile Country Code (MCC). According to https://en.wikipedia.org/wiki/International_mobile_subscriber_identity, the 3GPP specification 23.003 recommends that the "length of the MNC is uniform within a given MCC area". ...


1

This is not a full answer but I can't comment yet due to too less reputation, sorry. I+J seems to have a strong correlation with the temperature. I did a scatter plot of I+J vs. Temp and I can see at least one strong linear relationship (did not do the fit yet, though). You can also see some outliers but they seem to be parallel. You could think of a ...


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