- #1
alanveron
- 45
- 0
can anyone tell me how AM transmitter works?thanks
Here's a simple transmitter. http://www.scitoys.com/scitoys/scitoys/radio/am_transmitter.htmlalanveron said:can anyone tell me how AM transmitter works?thanks
NewScientist said:Average Supernova- where is it legal?! And the legality of transmitting has a lot to do with waelengths.
Part 15 of Title 47 of the Federal Code of Regulations addresses the construction of homemade AM band transmitters. The three most germane paragraphs follow:
§ 15.5 (General conditions of operation)
(a) Persons operating intentional or unintentional radiators shall not be deemed to have any vested or recognizable right to continued use of any given frequency by virtue of prior registration or certification of equipment, or for power line carrier systems, on the basis of prior notification of use pursuant to § 90- 63(g) of this chapter.
(b) Operation of an intentional, unintentional, or incidental radiator is subject to the conditions that no harmful interference is caused and that interference must be accepted that may be caused by the operation of an authorized radio station, by an other intentional or unintentional radiators by industrial, scientific and medical
(ISM) equipment, or by an incidental radiator.
(c) The operator of a radio frequency device shall be required to cease operating the device upon notification by a Commission representative that the device is causing harmful interference. Operation shall not resume until the condition causing the harmful interference has been corrected.
(d) Intentional radiators that produce Class B emissions (damped wave) are prohibited.
§ 15.23 Home-built devices.
(a) Equipment authorization is not required for devices that are not marketed, are not constructed from a kit, and are built in quantities of five or less for personal use.
(b) It is recognized that the individual builder of home-built equipment may not possesses the means to perform the measurements for determining compliance with the regulations. In this case, the builder is expected to employ good engineering practices to meet the specified technical standards to the greatest extent practicable. The provisions of § 15.5 apply to this equipment.
§ 15.219 Operation in the band 510-1705 kHz.
(a) The total input power to the final radio frequency stage (exclusive of filament or heater power) shall not exceed 100\milliwatts.
(b) The total length of the transmission line, antenna and ground lead (if used) shall not exceed 3 meters.
(c) All emissions below 510 kHz or above 1705 kHz shall be attenuated at least 20 dB below the level of the unmodulated carrier. Determination of compliance with the 20 dB attenuation specification may be based on measurements at the intentional radiator's antenna output terminal unless the intentional radiator uses a permanently attached antenna, in which case compliance shall be demonstrated by measuring the radiated emissions.
-newScientist
aren't you thinking of FREQUENCY modulation?Averagesupernova said:You're a bit off rogue. You make no mention of sidebands, the fact that the carrier does NOT change in amplitude when modulation is applied, various other tidbits...
can anyone tell me how AM transmitter works?thanks
Rogue Physicist said:aren't you thinking of FREQUENCY modulation?
Okay you've really lost me:You make no mention of ...the fact that the carrier does NOT change in amplitude when modulation is applied...
Rogue Physicist said:Okay you've really lost me:
Amplitude Modulation is EXACTLY about having the carrier change in amplitude by applying modulation.
Say what? Here's a good definition of Amplitude Modulation.Averagesupernova said:No it isn't. That is the perceived result as well as the perceived method of obtaining a result.
You have also spoken as though amplitude and power were identical, or have confused them. Of course the power, or rather average power of the signal is constant. The amplitude (i.e. the instantaneous voltage traced by an oscilliscope as the signal varies via modulation) is something else again, and varies (alot) according to the content of the modulating signal and the percentage of modulation.The strength of the carrier signal itself does NOT vary in amplitude after the modulation is added. It is still 100 watts.
An AM transmitter is a device that generates radio waves in the amplitude modulation (AM) format. It is used to transmit audio signals through radio waves, allowing for the broadcast of AM radio stations.
An AM transmitter works by first converting the audio signal into an electrical signal using a microphone or other input device. This electrical signal is then amplified and used to modulate the amplitude of a carrier wave, which is then transmitted through an antenna.
The main components of an AM transmitter include an audio input device (such as a microphone), an amplifier, a modulator, a carrier wave generator, and an antenna. Some transmitters may also have additional components such as filters and oscillators.
One of the main advantages of using an AM transmitter is that it allows for long-range transmission of radio signals. It is also a relatively simple and cost-effective technology compared to other forms of radio transmission. Additionally, AM signals can be easily received by most radios, making it a popular choice for broadcasting.
One limitation of an AM transmitter is that it is susceptible to noise interference, which can affect the quality of the audio signal. Additionally, AM signals have a limited bandwidth, which means they can only transmit a limited range of frequencies. This can result in lower sound quality compared to other forms of radio transmission.