R-TASC Video Series
Detailed, step-by-step description to perform the RTASC Tests for Microphone, Loudspeaker, Reference Channels and Basic AEC.
0. REAL TIME AUDIO SYSTEMS CHECK SETUPGetting started with the Real-Time Audio Systems Check process including the essential equipment and setting up Audio Weaver. By verifying the hardware and software functionality of an audio product, the Device Under Test, the R-TASC process can identify multiple issues typically found at the start of development. The test procedure is designed for OEMs making voice-enabled products including both microphones and loudspeakers and intended for hardware engineers and embedded software engineers. No DSP knowledge is required.
1. MICROPHONE MATCHING CHECKThe first step in the R-TASC process for microphones: preparing and running the microphone matching check. This test aims at determining if there are any gains/short circuits/noise induced by the system in the microphone input channels. If your microphones are not matched to within +/- 1 dB, you will lose performance in beamforming. This can be helped with trim gains during the tuning phase.
2. MICROPHONE SENSITIVITY CHECKThe second step in the R-TASC process for microphones: the preparing and running the microphone sensitivity check. The microphone sensitivity test verifies the sensitivity of each microphone channel based on specs in the microphone datasheet.
3. MICROPHONE CLIPPING CHECKThe third step in the R-TASC process for microphones verifies the sealing of the individual microphones. Note to wear hearing protection during this test. If the sine wave is showing a “flat top” instead of a curve, it is clipping.
4. MICROPHONE ISOLATION CHECKThe fourth step in the R-TASC process for microphones: the microphone isolation check requires pink noise from an external loudspeaker. Correct sealing indicates that there are no air gaps between the microphones which would otherwise make it difficult to distinguish which direction the voice or sound is coming from.
5. MICROPHONE NOISE FLOOR CHECKThe fifth step in the R-TASC process for microphones: the microphone noise floor check requires the microphone product data sheet and aims at verifying that the microphone channels do not contain electrical noise.
6. MICROPHONE FREQUENCY RESPONSE CHECKThe sixth step in the R-TASC process for microphones: the microphone frequency response check requires pink noise from an external loudspeaker.
7. MICROPHONE SAMPLE RATE CHECKThe seventh step in the R-TASC process for microphones: the microphone sample rate check requires a 1kHz tone from an external loudspeaker.
8. MICROPHONE CONTINUITY CHECKThe eighth step in the R-TASC process for microphones: the microphone continuity check requires an 800Hz sine tone from an external loudspeaker. If you see more than 16 cycles, the sampling rate is too low. If you see less than 16 cycles, the sampling rate is too high. If the sine wave is distorted, there are clocking issues in the audio driver.
9. LOUDSPEAKER THD CHECKThe loudspeaker THD check identifies potential problems in the device speaker that may affect AEC performance. Test engineers performing this step in the R-TASC should wear hearing protection.
10. LOUDSPEAKER CONDUCTED NOISE CHECKThe conducted noise check identifies mechanical sealing problems between the microphone and speaker internally within the device. Sealing flaws may cause mechanical coupling when the device speaker is playing sound, resulting in false values in the microphones. AEC performance will suffer if there is conducted noise through the device.
11. AEC TESTRunning the Acoustic Echo Cancellation test provides an estimated AEC performance of the Device Under Test. The test measures how much noise cancellation is taking place when the device is playing sound. Sufficient noise cancellation ensures that user speech will be distinguishable from the output.