已知某随机函数<img title="image.png" alt="image.png" src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/4e7ab36d38484ab691fb5a5f0e8eda77.png"/> 的相关函数为指数函数型<img title="image.png" alt="image.png" src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/15bc9aaa1fde474f9e5798fa1391340b.png"/>，式中<img title="image.png" alt="image.png" src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/be6dbfea8521487e81a097250ab27947.png"/>，<img title="image.png" alt="image.png" src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/e7c298ece88245109fa2390769106834.png"/>为常数。试求该过程的谱密度<img title="image.png" alt="image.png" src="https://image.zhihuishu.com/zhs/onlineexam/ueditor/202007/fc7ecbfea49c4e529e56ee5de3aedc26.png"/>。