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indirect FM transmitter is the transmitter which indirected connectly to the FM
INDIRECT FM GENERATION
While it is not possible to vary the frequency of a crystal oscillator directly, it is possible to vary its phase. The resulting PM signal can be used to create FM. This is the basis of the Armstrong modulator.
The mathematics required to analyze the Armstrong modulator completely are complex, so we will discuss only the basic circuit operation. An audio signal is passed through a preemphasis network and then an integrator, a special network whose output is the time integral of the input signal. The preemphasized integrated signal is used to phase modulate a crystal oscillator. Mathematically, it can be shown that PM using the integral of the audio signal is identical to FM using the audio signal itself. In this way an FM signal is generated.
The Armstrong modulator cannot produce much deviation, so combination of multipliers and mixers are used to raise the carrier frequency and the deviation. The multipliers are used to multiply the carrier and the deviation. The mixers are used to decrease the carrier, while keeping the deviation constant so that additional multiplier stages can be used to obtain more deviation. It is worth going through an example:
An FM station is authorized to operate at 90.9 MHz, with maximum deviation of 75 KHz. The FM signal is generated with an Armstrong modulator whose output is 500 KHz with a deviation of 15.432 Hz. The modulator output is applied to 3 triplers and a doubler to obtain a frequency of 81 MHz and a deviation of 2.5 KHz. The 81 MHz signal is mixed with a 77.97 MHz signal to produce a 3.03 MHz signal whose deviation is still 2.5 KHz. This signal is fed through a doubler, tripler and quintupler to multiply the carrier to 90.9 MHz and the deviation to 75 KHz.
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What is the frequency swing of an FM broadcast transmitter when modulated to 60 percent?
The maxium frequency swing in FM is ± 75 kHz so 75 kHz x 60% = ± 45 kHz
What frequency range does the US use for FM broadcasting?
60hz frequency is being used in us
Block diagram of FM transmitter?
very rough: +---+ |##| +---+
What is a studio-transmitter link?
A studio-transmitter link (STL) is just that. It is the link between the studio and the transmitter. Let's look at one in action. KWIZ radio is a hip FM station with studios on the top floor of the insurance building downtown. They got a good deal on the space, and they like being downtown 'cause it makes them (and their listeners) feel more connected. Their transmitter is located on top of Mount Fritz, some 20 miles away. The transmitter is up there because real estate is a bit cheaper there, and from that spot it can hit (reach) a lot of territory. And the tower doesn't have to be super tall, either. Besides, there isn't any place downtown to put up an FM broadcast antenna. If the antenna was downtown, it would have to be super tall. And it couldn't get the kind of coverage KWIZ can get with a transmitter located up on a big hill. They want lots of area where their signal can reach out to and arrive at receivers. That translates into lots of listeners and lots of opportunities to sell radio ads and get lots of money for them because the station has lots of coverage/listeners. Dusty Rhodes and Sandy Beach share the mic on the morning show. They draw music from the tracks stored in the memory of the station's music computer. (Who still uses CD's?) When they play a tune, the signal is routed to the input of a microwave transmitter on the roof of the insurance building. The microwave transmitter takes that signal and uses it to modulate the microwave carrier, and then the modulated carrier is sent through amplifiers and finally to a microwave power amplifier. From there, it is sent into a waveguide (or, more probably, a length of heliax cable) and routed to the little microwave dish on that short mast on the roof. The dish is a parabolic reflector, and it may be anything from a foot or two across to half a dozen feet across, depending on the system used and the distance it needs to cover. (A meter in diameter would not be uncommon for something like this.) The microwave signal is then radiated from the feedhorn into the dish. From there it is reflected off the dish and goes where the dish is pointed. The transmitter's dish is pointed at a similar receiver dish up on Mount Fritz. That receiver dish (which is pointed at the transmitter dish) is often mounted on the tower that the FM broadcast antenna sits on. The microwave signal is collected on that second dish and reflected to the focal point to be gathered up by a horn positioned appropriately. There may be a low noise amplifier built right into the horn at the focal point of the receiver's dish. The microwave signal is then demodulated and music track recovered. Then that signal can then be used to modulate the FM transmitter, which is right there. The amplified signal goes out of the FM transmitter and into the transmission line which connects the transmitter to the antenna. The signal is being routed point to point from the studio to the transmitter. And that's the studio-transmitter link (STL) that is common today. AM and FM radio stations and also the TV stations use the links commonly.
How to Calculate Pressure Transmitter Accuracy?
accuracy with only one variable. Accuracy takes into account several different variables, only one of which is non-linearity. In other words, non-linearity alone does not determine a device’s overall accuracy. These are the five variables a user should consider when determining pressure transmitter accuracy: Two methods are used to generate the reference line needed to find a pressure transmitter’s non-linearity: the terminal method, also called endpoint method (blue line) and the best fit straight line method (brown line). The linearity is the largest deviation from the reference line to the actual response (red line). Non-linearity Non-linearity is the largest deviation between the actual response (red curve) and a reference line. There are two common methods for generating this reference line The terminal method, also called the endpoint method, draws a straight line from the actual zero point to the actual full scale value endpoint. Since this method is based on the characteristic curve’s endpoints, it is a truer representation of a pressure transmitter’s non-linearity. The best fit straight line (BFSL) method is a straight line that stays within a certain percentage deviation from the characteristic curve, or actual response. The endpoints do not figure into this method. BFSL method values are typically half of terminal method values, meaning that a pressure transmitter with a ±0.25% BFSL non-linearity allows for a ±0.50% error. Zero offset and span tolerance when calculating pressure transmitter accuracy Zero offset The zero offset is the deviation between the ideal line’s zero point and the characteristic curve’s zero point (see Fig. 4). Span tolerance Span tolerance is the deviation of the actual span from the ideal span between the zero point and the full scale point. The span offset is not related to the zero offset and has to be added to it. Hysteresis Hysteresis is the lag between a change in pressure and the corresponding change in the pressure transmitter signal. It is an indication of how fast or slow a pressure transmitter responds to input changes. Non-repeatability Non-repeatability is the maximum difference in the signal of the pressure transmitter for the same applied pressure. It is an indication of how much the transmitter duplicates measurements for the same input.
What is indirect FM transmitter?
It's Rachev theory. :)
What is Armstrong indirect FM transmitter?
It's Rachev theory. :)
Frequency modulation direct and indirect FM generation method?
I know the answer,but I just can reply it in Chinese.
What is FM transmitter and what are the different FM transmitters?
FM transmitter : In this case the frequency of a carrier signal is modulated/altered in accordance with that of frequency of modulating signal. TYPES OF FM TRANSMITTER: 1> directly modulated FM transmitter. 2>indirectly modulated FM transmitter. an FM transmitter is a portable device that plugs into the headphone jack or proprietary output port of a portable audio or video device, such as a portable media player, CD player, or satellite radio system. The sound is then broadcast through the transmitter, and plays through an FM broadcast band frequency. Purposes for an FM transmitter include playing music from a device through a car stereo, or any radio.
Where can I find the the best FM transmitter?
From the research I have done, the best FM transmitter will depend on what you are using it for. Two that I found come rated with 4 and 1/2 stars are the Belkin TuneCast F8Z498-P FM Transmitter and the Griffin itrip auto fm transmitter for ipod.
What does a fm transmitter mp3 usb do exactly?
An fm transmitter mp3 usb allows you to play your digital music in your car. You do not have to listen to the music on the radio but you can put songs on the transmitter so that songs on your mp3 player can be played in your car. Go to http://www.amazon.com/Car-MP3-Transmitter-Drive-Remote/dp/B000O3PLYS for examples of transmitters.
What is a itrip transmitter?
an iTrip transmitter is an FM transmitter that is compatible with Apple iPods. You can plug in your iPod, and it will play your music through an intermittent FM station.
Does e72 has FM transmitter?
no
Where do I buy a cheap FM transmitter for my iPod?
The best place to find a FM transmitter for your iPod is at Best Buy. You can also go online and use their website to find out the price regarding the FM transmitter.
Why power amplifier used in FM transmitter?
Amplifier is used in an FM transmitter to increase the level of a signal suitable for transmission
What devices can be used with an FM mp3 transmitter?
There are several different devices that can be used with an FM mp3 transmitter. Devices such as a portable CD player, portable DVD player, and satellite radios can be used with an FM mp3 Transmitter.
How do you send an MP3 to FM without a transmitter and MP3 player?
i won't send an mp3 to fm without a transmitter and mp3 player.
