the maximum amplitude of carrier wave varied with respect to instantaneous values of message signal is called amplitude modulation
amplitude modulating signal
Not sure what type of modulation you are looking for, but there are two that can be manipulated, either individually or in conjunction:Frequency modulation index refers to the relation between the sine wave frequency (sine_freq) and the triangle (or saw-tooth) wave frequency (triang_freq).The frequency modulation index is equal to ((triang_freq)/(sine_freq)).Amplitude modulation index refers to the relation between the sine wave amplitude (sine_amp) and the triangle (or saw-tooth) wave amplitude (triang_amp).The amplitude modulation index is equal to ((sine_amp)/(triang_amp)).Varying the modulation index (normally by varying the frequency or amplitude of the triangle wave form) changes that respective modulation index.From personal experience, an appropriate amplitude modulation index for an SPWM waveform should be around 0.8(that is, if the triangle has an amplitude of 10, the sine would have an amplitude of 8). This index should never be equal to 1 (one); it should always be less. A.K.A.: the triangle-wave amplitude should always be greater than the sine-wave.On the other hand, a triangle-wave frequency much greaterthan the sine-wave frequency makes an SPWM that in turn generates a "cleaner" synthesized sine-wave in the H-bridge you are probably using. Try different freq. modulation indexes, but an index of at least 10 should be used (preferably somewhere around 100 if you want a good SPWM). That is, if the sine-wave frequency is 60 Hz, the triangle-wave frequency should be above 600, preferably 6,000 or more. Complications in the filter design in the "output" of the H-bridge will vary greatly when playing around with the frequency modulation index. That being said, keeping the amplitude modulation index at a static 0.8, and playing around with the triangle-wave frequency should be your best bet.
Modulation Index is the ratio of the maximum deviation frequency to the frequency of modulation. In other words it is the ratio of the spread in frequency spectrum to the frequency that was used to modulate the carrier. For FM, modulation index is given by the formula mf= df/f where, mf=modulation index for FM df=difference in carrier frequency f=frequency of the signal
the modulation system is of FM
Deviation ratio: In a frequency modulation system, the ratio of the maximum frequency deviation of the carrier to the maximum modulating frequency of the system under specified conditions
The values of amplitude modulation index is categorized as an objective type.
The range of modulation index in amplitude modulation (AM) is typically between 0 and 1. A modulation index of 0 indicates no modulation, while a modulation index of 1 represents full modulation where the carrier signal amplitude varies from zero to peak value.
amplitude modulating signal
A(m)/A(c)=0.5 is known as 50% modulation index. where, A(m)=amplitude of message signal A(c)=amplitude of carrier signal
In amplitude modulation, modulation depth refers to the ratio of the unmodulated carrier amplitude to the amplitude deviation for which the modulated carrier wave reaches its minimum value. If this minimum value is zero, the modulation depth is 100%.For amplitude modulation,modulation depth = (a-b)/(a+b),wherea is the unmodulated carrier amplitude, andb is the minimum amplitude deviation.The modulation depth ratio is also referred to as the modulation index.
In amplitude modulation, modulation depth refers to the ratio of the unmodulated carrier amplitude to the amplitude deviation for which the modulated carrier wave reaches its minimum value. If this minimum value is zero, the modulation depth is 100%.For amplitude modulation,modulation depth = (a-b)/(a+b),wherea is the unmodulated carrier amplitude, andb is the minimum amplitude deviation.The modulation depth ratio is also referred to as the modulation index.
In frequency modulation (FM) the amplitude does not remain constant. Instead, the amplitude varies according to the modulation index and the frequency of the modulating signal. This is in contrast to amplitude modulation (AM), where the amplitude of the carrier signal is modulated while the frequency remains constant.
Amplitude modulation (AM) is a method of impressing data onto an alternating current waveform by varying its amplitude in relation to the data being sent. The main characteristics of AM include the modulation index, which determines the amount of variation in the carrier wave, and the sidebands that are created as a result of modulation. AM is susceptible to noise and interference due to its reliance on the amplitude of the signal.
Not sure what type of modulation you are looking for, but there are two that can be manipulated, either individually or in conjunction:Frequency modulation index refers to the relation between the sine wave frequency (sine_freq) and the triangle (or saw-tooth) wave frequency (triang_freq).The frequency modulation index is equal to ((triang_freq)/(sine_freq)).Amplitude modulation index refers to the relation between the sine wave amplitude (sine_amp) and the triangle (or saw-tooth) wave amplitude (triang_amp).The amplitude modulation index is equal to ((sine_amp)/(triang_amp)).Varying the modulation index (normally by varying the frequency or amplitude of the triangle wave form) changes that respective modulation index.From personal experience, an appropriate amplitude modulation index for an SPWM waveform should be around 0.8(that is, if the triangle has an amplitude of 10, the sine would have an amplitude of 8). This index should never be equal to 1 (one); it should always be less. A.K.A.: the triangle-wave amplitude should always be greater than the sine-wave.On the other hand, a triangle-wave frequency much greaterthan the sine-wave frequency makes an SPWM that in turn generates a "cleaner" synthesized sine-wave in the H-bridge you are probably using. Try different freq. modulation indexes, but an index of at least 10 should be used (preferably somewhere around 100 if you want a good SPWM). That is, if the sine-wave frequency is 60 Hz, the triangle-wave frequency should be above 600, preferably 6,000 or more. Complications in the filter design in the "output" of the H-bridge will vary greatly when playing around with the frequency modulation index. That being said, keeping the amplitude modulation index at a static 0.8, and playing around with the triangle-wave frequency should be your best bet.
The modulation index formula in frequency modulation (FM) is given by the equation: β = Δf / fm, where β is the modulation index, Δf is the peak frequency deviation, and fm is the modulating frequency. Modulation index indicates how much the carrier frequency is being varied by the modulating signal in FM.
Modulation index is also called as Modulation depth. The modulation index of a modulation scheme describes by how much the modulated variable of the carrier signal varies around its unmodulated level.
how modulation index varies for FM