· These new frequencies can be seen in the frequency spectrum as shown in the figure below. The Signal component above the carrier frequency is known as Upper Sideband and the signal below the carrier frequency is known as Lower Sideband. The upper sideband f(USB) and lower sideband f(LSB) are calculated as: fUSB = fc +fm and fLSB = fc – fmEstimated Reading Time: 5 mins Using special circuits and filters, single sideband transmissions can consist of either the lower sideband (LSB) or the upper sideband (USB). If you listen to an SSB signal on an AM receiver, the voices are altered and sound very muffled, garbled and distorted. Some people even say "Donal Duck" sounding when tuned improperly in the sideband mode Single sideband (SSB) is a common analog modulation scheme for voice communications. With SSB only one sideband—either the upper or the lower—is present in the modulated carrier. That is acceptable because the two sidebands contain the same information, so the elimination of one sideband does not cause a loss of information
What is Sideband | Single Sideband, DSB-SC, and Vestigial ()
Lower single sideband are many users of single sideband modulation. Many users requiring two way radio communication will use single sideband and they range from marine applications, generally HF point to point transmissions, military as well as radio amateurs or radio hams. Single sideband modulation or SSB is derived from amplitude modulation AM and SSB modulation overcomes a number of the disadvantages of AM.
Single sideband modulation is normally used for voice transmission, but technically it can be used for many other applications where two way radio communication using analogue signals is required.
As a result of its widespread use there are many items of radio communication equipment designed to use single sideband radio including: SSB receiver, SSB transmitter and SSB transceiver equipments.
Single sideband, SSB modulation is basically a derivative of amplitude modulation, AM. By removing some of the components of the ordinary AM signal it is possible lower single sideband significantly improve its efficiency. It is possible to see how an AM signal can be improved by looking at the spectrum of the signal. When a steady state carrier is modulated with an audio signal, for example a tone of 1 kHz, lower single sideband, then two smaller signals are seen at frequencies 1 kHz lower single sideband and below the main carrier.
If the steady state tones are replaced with audio like that encountered with speech lower single sideband music, these comprise lower single sideband different frequencies and an audio spectrum with frequencies over a band of frequencies is seen, lower single sideband. When modulated onto the carrier, these spectra are seen above and below the carrier.
It can be seen that if the top frequency that is modulated onto the carrier is 6 kHz, then the top spectra will extend to 6 kHz above and below the signal. In other words lower single sideband bandwidth occupied by the AM signal is twice the maximum frequency of the signal that is used to modulated the carrier, i, lower single sideband.
it is twice the bandwidth of the audio signal to be carried. Amplitude modulation is very inefficient from two points, lower single sideband. The first is that it occupies twice the bandwidth of the maximum audio frequency, and the second is that it is inefficient in terms of the power used. The carrier is a steady state signal and in itself carries no information, only providing a reference for the demodulation process.
Single sideband modulation improves the efficiency of the transmission by removing some unnecessary elements, lower single sideband. In the first instance, the carrier is removed - it can be re-introduced in the receiver, and secondly one sideband is removed - both sidebands are mirror images of one another and the carry the same information. While signals that use single sideband modulation are more efficient for two way radio communication and more effective than ordinary AM, they do require an increased level of complexity in lower single sideband receiver.
As SSB modulation has the carrier removed, this needs to be re-introduced in the receiver to be able to reconstitute the original audio. This is achieved using an internal oscillator called a Beat Frequency Oscillator BFO or Carrier Insertion Oscillator CIO. This generates a carrier signal that can be mixed with lower single sideband incoming SSB signal, thereby enabling the required audio to be recovered in the detector.
Typically the SSB detector itself uses a mixer circuit to combine the SSB modulation and the BFO signals. This circuit is often called a product detector because like any RF mixer the output is the product of the two inputs. Any deviation from this will cause the pitch of the recovered audio to change. Whilst errors of up to about Hz are acceptable for communications applications including amateur radio, if music is to be transmitted the carrier must be reintroduced on exactly the correct frequency.
This can be accomplished by transmitting a small amount of carrier, and using circuitry in the receiver to lock onto this. It is often necessary to define the output power of a single sideband transmitter or single sideband transmission. For example it is necessary to know the power of a transmitter used for two way radio communication to enable its effectiveness to be judged for particular applications.
Power measurement for an SSB signal is not as easy as it is for many other types of transmission because the actual output power is dependent lower single sideband the level of the modulating signal.
To overcome this a measure known as the peak envelope power PEP is used. This takes the power of the RF envelope of the transmission and uses the peak lower single sideband of the signal at any instant and it includes lower single sideband components that may be present. Obviously this includes the sideband being used, but it also includes any residual carrier that may be transmitted. The level of the peak envelope power may be stated in Watts, or nowadays figures quoted in dBW or dBm may be used.
These are simply the power levels relative to 1 Watt or 1 milliwatt respectively. As an example a signal of 10 watts peak envelope power is 10 dB above a 1 Watt signal and therefore it has a power of 10 dBW. Similar logic can be used to determine powers in dBm, lower single sideband. There are many variants of single sideband modulation that are used, and there are several different abbreviations for them, lower single sideband.
These are explained below, lower single sideband. LSB: This stands for Lower Sideband. This form of single sideband modulation is formed when the lower sideband only of the original signal is transmitted. Typically this is used by radio amateurs or radio hams on their lower single sideband below 9 MHz. USB: This stands for Upper Sideband. This form of single sideband modulation is formed when the upper lower single sideband only of the original signal is transmitted.
Typically this form of SSB modulation is used by professional users on all frequencies and by radio amateurs or radio hams on their allocations above 9 MHz. DSB: This is Double Sideband and it is a form lower single sideband modulation where an AM signal is taken and the carrier is removed to leave the two sidebands.
Although easy to generate, lower single sideband, it does not give any improvements in spectrum efficiency and it is lower single sideband not particularly easy to resolve. Accordingly it is rarely used. SSB SC: This stands for Single Sideband Suppressed Carrier.
It is the form of SSB modulation where the carrier is removed completely as opposed to SSB reduced carrier where some of the carrier is left. VSB: This stands for Vestigial Sideband. It is a form is signal where one sideband is completely present, lower single sideband, and the other sideband that has been only lower single sideband cut off or suppressed.
It is widely used for analogue television transmissions. It comes in useful because the baseband video signal is wide typically 6 MHz. To transmit this using AM would require a bandwidth of 12 MHz. To reduce the amount of spectrum used, one sideband is transmitted fully, whereas only the lower frequencies of the other are transmitted.
The high frequencies can be later enhanced using filters. SSB reduced carrier : In this form of SSB modulation one sideband is present along with a small amount of the carrier. For some applications, a small amount of carrier is kept. This may be used to provide a reference signal for accurate demodulation. Single sideband modulation is often compared to AM, of which it is a derivative. It has several advantages for two way lower single sideband communication that more than outweigh the additional complexity required in the SSB receiver and SSB transmitter required for its reception and transmission.
The summary of this is that SSB modulation offers a far more effective solution for two way radio communication because it provides a significant improvement in efficiency. Single sideband modulation, SSB is the main modulation format used for analogue voice transmission for two way radio communication on the HF portion of the radio spectrum. Its efficiency in terms of spectrum and power when compared to other modes means that for many years it has been the most effective option to use.
Now some forms of digital voice transmission lower single sideband being used, but it is unlikely that single sideband will be lower single sideband for many years as the main format used on these bands. What is single sideband modulation? Single sideband modulation It can be seen that if the top frequency that is modulated onto the carrier is 6 kHz, then the top spectra will extend to 6 kHz above and below the signal. SSB receiver While signals that use single sideband modulation are more efficient for two way radio communication and more effective than ordinary AM, they do require an increased level of complexity in the receiver.
Single sideband power measurement It is often necessary to define the output power of a single sideband transmitter or single sideband transmission. Single sideband modulation variants There are many variants of single sideband modulation that are used, and there are several different abbreviations for them.
SSB advantages Single sideband modulation is often compared to AM, of which it is a derivative. As only one sideband is transmitted the receiver bandwidth can be reduced by half. This improves the signal to noise ratio by a factor of two, lower single sideband, i. Summary Single sideband modulation, SSB is the main modulation format used for analogue voice transmission for two way radio communication on the HF portion of the radio spectrum. Previous page Next page.
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What is SSB: Single Sideband Modulation » Electronics Notes
· These new frequencies can be seen in the frequency spectrum as shown in the figure below. The Signal component above the carrier frequency is known as Upper Sideband and the signal below the carrier frequency is known as Lower Sideband. The upper sideband f(USB) and lower sideband f(LSB) are calculated as: fUSB = fc +fm and fLSB = fc – fmEstimated Reading Time: 5 mins Using special circuits and filters, single sideband transmissions can consist of either the lower sideband (LSB) or the upper sideband (USB). If you listen to an SSB signal on an AM receiver, the voices are altered and sound very muffled, garbled and distorted. Some people even say "Donal Duck" sounding when tuned improperly in the sideband mode Single sideband (SSB) is a common analog modulation scheme for voice communications. With SSB only one sideband—either the upper or the lower—is present in the modulated carrier. That is acceptable because the two sidebands contain the same information, so the elimination of one sideband does not cause a loss of information
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