about Local Oscillator block

2012 10 18
1 个回答
更新时间：2019 3 12
9 次查看（30 天）

1 个投票

Hi,
In the “Local Oscillator” block there are two parameters “Sample time” and “Frequency”. Must these two be related to Nyquist theory? That, 1/Sample time > 2 * Frequency.
Thanks Senmeis

1 个评论
显示 -1更早的评论 隐藏 -1更早的评论

Sree Vamsi
Sree Vamsi 2019-3-12
where can i find the local oscillator block ???
i need it for my receiver design.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

Azzi Abdelmalek
Azzi Abdelmalek 2012-10-18

1 个投票

  • The frequency is the repetition of your signal
  • The sample time is the interval of time between two values of your signal
both have nothing to do with Nyquist theorem. The sample time must be chosen respecting Shanon theorem

3 个评论
显示 1更早的评论 隐藏 1更早的评论

Owen
Owen 2012-10-26
Shanon has three theorems. Which one did you mean?
Can you give me an example of the meaning of "Sample time" here?
Thanks Senmeis
Azzi Abdelmalek
Azzi Abdelmalek 2012-10-26
编辑：Azzi Abdelmalek 2012-10-26
That depends on what are you sampling, a signal or a system, And what are your objectives: control system, communication,...
If you want to make a discret control system, you must discretize your models with a sample time ts, that means all the signals must be sampled with ts.In this case ts choosen compared to the constant time of the output we want to control
Also if our signal is naturaly discret, Shanon theorem has nothing to do with it
Owen
Owen 2012-10-30
It’s just an oscillator. The sample time shall only depend on its output frequency.
I have tried this block with different sample time and found out that the wished frequency can be obtained only if 1/Sample time > 2 * Frequency.
Is that not Nyquist theorem?
Senmeis

请先登录，再进行评论。

类别

在 帮助中心 和 File Exchange 中查找有关 Signal Operations 的更多信息

产品

标签

提问:

Owen
Owen
2012-10-18

评论：

Sree Vamsi
Sree Vamsi
2019-3-12

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by