HP-DK70M microphone array module

1、 Overview
In typical environments, noise always comes from all directions and crosses the frequency spectrum of speech signals. In addition, the effects of reverberation and reverberations make it very difficult to capture pure speech using a single microphone. The microphone array module (HP-DK70M) is a single directional microphone module designed and developed by Guangzhou Sizheng Electronics Co., Ltd. based on the circular array technology of 4 silicon microphone (MEMS) microphones. This product adopts a 4 microphone array and integrates algorithms such as noise suppression, reverberation suppression, echo cancellation, and fixed beam. It can effectively extract the speaker's speech in noisy sound field environments and reduce the interference of surrounding environmental noise. At present, it is widely used in smart finance, smart services, smart cars, smart homes, robots and other scenarios, and can provide corresponding solutions.

Figure 1

2、 System framework
The HP-DK70M adopts a circular quad microphone array design and supports the UAC2.0 audio protocol; Can support systems such as Windows, Linux, Android, etc

3、 Module size
1. The overall size is 80.5mm * 49mm * 1.6mm.

Data transfer protocol: USB 2.0.

4、 Acoustic and electrical parameters

Table 1 Acoustic Parameters

Table 2 Electrical Parameters

5、 Pick up direction and range angle
Identification of sound pickup hole: HP-DK70M uses a back inlet microphone, so the pickup surface should be the side without components. The sound pickup hole is shown in Figure 3 below

Figure 3 Sound Hole Collection

Pick up direction: The third microphone picks up sound in the M3 direction, as shown in Figure 4.

Pick up range: Based on the center of the microphone array, the plane is ± 45 °, and the pitch angle is 25 °.

Suppression of polarity: The polarity diagram measured at a frequency of 1KHz is shown in Figure 6, so the pickup range mentioned in the article is a reference range, and there is a certain attenuation transition section in actual pickup.

6、 Interface definition
The HP-DK70M module interface is connected through Type C, and the PCBA is shown in the following figure:

Figure 7 Physical picture of PCBA

7、 Hardware configuration and inventory
The hardware design adopts modular design principles, which are simple and easy to use. The motherboard supports multiple peripheral interfaces, including USB Audio and serial ports for output audio. It is drive free and can support systems such as Windows, Linux, and Android. The hardware configuration list is shown in Table 5-1, and the hardware inventory list is shown in Table 5-2.

Table 5-1 Hardware Configuration List

Table 5-2 Hardware List

8、 Precautions
1. When installing the finished structure, there should be sufficient space above the pickup surface for sound input, and it is recommended to have an open space without any sound insulation or obstruction;
2. The aperture D of the peripheral structure opening should be larger than the aperture d of the MEMS mic pickup hole, that is, D>d;
3. When assembling, the sound hole surface of the PCBA board should be tightly attached to the inner wall of the peripheral structural components, and the tighter the better, to avoid the formation of sound cavities. At least 2D>h is required.