The present invention includes an optical system disposed on an optical path of light that is emitted by a light emitting section, travels to a detection target object, is reflected by the detection target object, and reaches a light receiving section. The method includes the step of determining whether a number of multiple user elements within a multi-user multiple-input multiple-output group is greater than the number of resource blocks allocated to the MU-MIMO group. An implantable sensor such as an accelerometer or a microphone senses an acoustic signal indicative heart sounds including S3. Presentation of the audio data is delayed by this difference in time to synchronize presentation of the audio data with presentation of the video data. In that manner, the braze retention structures keep braze material from accumulating in unwanted areas where it could adversely affect hermeticity as well as proper attachment of an EMI filter to the feedthrough assembly. In one embodiment, a gradient delay can be determined and used to calibrate an MRI apparatus.