Amplitude Modulation (AM) modulates a signal by varying the amplitude of the carrier. The ease with which it can be demodulated made AM radio broadcasting popular before FM demodulation was cost effective.

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Singnals, filters and power output

I have couple of questions: A square signal goes through a low pass filter and in the output of a circuit we get a sine. What happens there? Give a scheme? This is really weird, because, from what ...
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107 views

Why AM is preferred over FM in long distance communication?

In almost all long distance communication AM is preferred over FM. Do type of modulation has anything to do with this or it is just depending on transmitting frequency?
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Radio Receiver IC

I am a Junior EE student that is interested in putting together a small radio receiver project for fun and to get some general practice with design. I have found these receiver chips from Silicon Labs ...
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138 views

Problem solving super heterodyne receiver question

I have two problems which i am trying to solve but i am stuck on the half way. I have the following first question, which i am trying to solve I have solved the problem as following, ...
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3answers
114 views

Inductor specifications for AM circuits

I am working with the book "Build Your Own Transistor Radios" by Ronald Quan in which he has a lot of AM projects. I am having a hard time figuring out what I need to buy from his specifications. For ...
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2answers
158 views

What is the tiniest, low-power, and efficient am transmitter?

Here are my constraints: I need to build an am transmitter, but it has to fit in a 1 inch diameter and ~1 inch height box. Since the box is very small, I plan to use a CR2032 battery, which is also ...
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101 views

What is the modulation technique used?

I own a Tx/Rx Radio Direction-Finding (RDF) set for a sport called falconry, basically, locating & recovering a pet falcon after flight. The Tx tag is at 218.025MHz from Marshall Radio Telemetry ...
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1answer
107 views

Making an AM radio with a silicon diode

I've been working a few days on this and have still come up with nothing. I am trying to make an AM radio using a silicon diode, but all of my attempts have failed. I believe my latest attempt most ...
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6answers
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building simple radio

I'd like to build a simple AM radio (so simple it will only receive a single AM channel). What is the simplest way to build a single channel AM radio that will output to an 8ohm speaker? (e.g. 1030 ...
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114 views

How to obtain the in-phase carrier for synchronous detection of an AM signal?

I am designing an AM receiver that has a carrier frequency of 2MHz with a bandwidth of 20kHz; i.e., the information signal has 10kHz bandwidth. What I've designed is basically like this: So I need ...
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91 views

AM demodulation circuit

From the receiver circuit below, which is exactly the part that demodulates the RF signal? I know, a typical circuit used for an envelope detector is composed of a resistor, a capacitor and a diode. ...
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3answers
126 views

How to receive faint AM light

I am going to be amplitude modulating a high power LED light from a peak on a mountain. I want to recieve this faint light as far as physically possible before the light fades out too much to recieve. ...
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2answers
141 views

Determining type of modulation

The circuit below is a radio transmitter circuit of a typical RC car. The circuit makes use of IC TX2 encoder. The output of IC ("SO" pin) is a series of pulses at low speed (84 Hz). This signal will ...
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How can I Amplitude Modulate this?

I recently built this circuit, and could hear a nice full quieting signal on my short-wave radio with a 7.2 megahertz crystal for the 40 meter band. What is the simplest way I could Amplitude ...
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146 views

Amplitude modulated wave weird display in oscilloscope

In my lab experiment (http://www.ele.uri.edu/courses/ele436/labs/expA2.pdf), My amplitude modulated wave is not displaying the vertical lines-the high frequency waves of carrier (as shown in ...
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3answers
177 views

Can a Digital Signal Transceiver be made using AM?

I want to make a simple wireless thermometer using TMP36. I've seen people making it using Xbee and some RF modules but I want to know if I can use a simple AM transceiver instead of specific RF ...
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3answers
209 views

Small Signal RF Amplifer Limitations

Question: I am designing the following common emitter amplifier. This is designed with a BC547B transistor. My design is as follows: Vcc = 15V, IC = 30ma, VRe = 2.5 V, VRc = 5V, VCE = 7.5V. HfE = ...
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1answer
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Amplitude Modulation Circuit Components

How does one select the values of components used in Amplitude Modulation Circuit (using a Transistor common emitter amplifier circuit)? The circuit that I designed ends up giving a weird waveform ...
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The primary selection criteria for choosing FM vs. AM is dynamic range

The primary reason for selecting FM over AM is the ability of FM to support a greater dynamic range by spreading the information across a wide range of frequencies, and using more 'horizontal ...
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Final RF envelope of FM and AM are the same

https://masi.vuse.vanderbilt.edu/images/0/0b/EECE_252_Final_Project2.pdf Page 2 spectrum plots. Effective RF electromagnetic power profile is effectively the same for baseband audio content ...
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172 views

Is FM more information density efficient than AM

So here and here, RF power envelope We have determined the information expressed in an AM signal comes from the fact that the amplitude of electromagnetic energy at any given frequency determines ...
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109 views

RF power envelope

If I have an oscillator at 10 kHz outputting 5 W, using AM, like this. Where does the power in the sidebands come from? Is the power the result of the harmonic relationship between the carrier and ...
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1answer
210 views

AM and Suppressed carrier SSB

So if I have AM, then to transmit information, I modulate the amplitude of energy peaks in a wave that has a frequency of say 10 kHz. So normally, the individual peaks in the wave occurring at ...
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AM Modulator Mixer Circuit

I found a very basic AM transmitter circuit on the youtube video here. The schematic is below: I'm a bit confused on the op-amp circuit on the right. It seems that the op-amp is really only ...
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why frequency modulated signal covers small area as compare to am signal [closed]

why frequency modulated signal covers small area as compare to AM signal ?
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562 views

Building an AM receiver for 10Mhz (NIST WWV)

I've read a vast amount of information on this topic. I'm trying to prototype in a circuit simulator and it seems that there is a bug with transistors. Hit the reset button to mess it up. Even when ...
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1answer
464 views

long wave radio receiver circuit

I wish to build a radio which can receive on 60khz am. What is the simplest circuit that will achieve this. Assuming a ferrite rod in a inductor/capacitor configuration, how would I tune this setup?
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161 views

RC AM senders/recievers: Changing the crystals, and using Servo PPM as a 1/0 switch

I am trying to use a 27mhz RC car controller to send to an RC Car AM reciever and use that output (short 1-1.5ms pulse of a few mA) to trigger a 5V relay, with the signal stabilised via a ...
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Building radios using RLC Meter

I'm interested in building AM and FM radios from discrete components. Has anyone ever used an RLC meter to precisely create the inductors and other elements used in these radios? I know cheaper RLC ...
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2answers
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Making a suitable antenna for a crystal radio

I'm trying to build a simple AM crystal radio, however, I'm not getting any voltage registered when using it. This is the kind that's only powered by the radio waves. The site I was using to design it ...