ASN9 - 3rd Harmonic & QSD: Difference between revisions
Jodi.Hodge (talk | contribs) No edit summary |
Jodi.Hodge (talk | contribs) No edit summary |
||
(20 intermediate revisions by the same user not shown) | |||
Line 1: | Line 1: | ||
[[Jodi Hodge|Back to my home page]] |
[[Jodi Hodge|Back to my home page]] |
||
Asignment: Explain Third Harmonic and Quadrature Sampling |
|||
'''Third Harmonic Sampling''' |
|||
[http://www.groups.yahoo.com/group/softrock40 Soft Rock] |
|||
⚫ | |||
The cosine series is made up of a infintie sum of harmonics |
|||
Third Harmonic Sampling |
|||
<math> |
<math> |
||
\sum_{n=1}^{\infty} \frac{1}{n} cos(n \omega t) = cos(\omega t) + \frac{1}{2}cos(2\omega t) + \frac{1}{3}cos(3\omega t) + \frac{1}{4}cos(4\omega t) + \cdots </math> |
\sum_{n=1}^{\infty} \frac{1}{n} cos(n \omega t) = cos(\omega t) + \frac{1}{2}cos(2\omega t) + \frac{1}{3}cos(3\omega t) + \frac{1}{4}cos(4\omega t) + \cdots </math> |
||
Third harmonic sampling is used in some applications, such as the SoftRock-40 software defined radio, to divide the local oscillator frequency by three. |
|||
The third harmonic is the third term |
|||
Third Harmonic Sampling |
|||
<math> \frac{1}{3}cos(3\omega t)</math>. |
|||
The benefit of using the third harmonic for sampling in a circuit rather than than the first harmonic is that it creates an oscillation that is three times as fast. SoftRock -40 software defined radio for example uses third harmonic sampling as a technique to obtain faster oscillation. In addition, third harmonic sampling is that it is cheaper to buy a low frequency oscillator and the parts driven by one. The disadvantage is that it results in power loss of -9.54dB.See how Softrock uses Third Harmonic Sampling[http://www.groups.yahoo.com/group/softrock40 Soft Rock] |
|||
'''Quadrature Sampling''' |
|||
A Quadrature is output signal that is a phase off from the output signal. For example, in a software define radio two signals that are generated from two mixers are phase shifted 90 degrees. One signal is the desired signal and the second is the quadrature signal that is used for quadrature sampling. |
|||
Further information on Quadrature Sampling |
|||
⚫ |
Latest revision as of 13:50, 19 December 2009
Third Harmonic Sampling
The cosine series is made up of a infintie sum of harmonics
The third harmonic is the third term
.
The benefit of using the third harmonic for sampling in a circuit rather than than the first harmonic is that it creates an oscillation that is three times as fast. SoftRock -40 software defined radio for example uses third harmonic sampling as a technique to obtain faster oscillation. In addition, third harmonic sampling is that it is cheaper to buy a low frequency oscillator and the parts driven by one. The disadvantage is that it results in power loss of -9.54dB.See how Softrock uses Third Harmonic SamplingSoft Rock
Quadrature Sampling
A Quadrature is output signal that is a phase off from the output signal. For example, in a software define radio two signals that are generated from two mixers are phase shifted 90 degrees. One signal is the desired signal and the second is the quadrature signal that is used for quadrature sampling.
Further information on Quadrature Sampling