1.2
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10/08/2021
Infineon UltraHub
User manual
3
Ultrasonic transmission configuration
3.1
Enabling ultrasonic transmission
The four channels on the sensing shields all record audio signals continuously. The ultrasonic transmitting
functionality can instead be configured depending on which of the four channels is required to transmit the
ultrasonic bursts according to the pulse-echo principle.
Default configuration sees only channel 1 active as transceiver, i.e., sending and receiving, and channels 2, 3
and 4 inactive, i.e., receiving only. Figure 10 illustrates the actuation patterns for the default configuration (A)
as well as custom configuration (B), with all four transceivers active in sending mode.
Figure 10
Examples of actuation signals for default (A) and custom configuration with all channels
active (B)
3.2
Transmitting burst design
The ultrasonic transmitting patterns can be configured using a selection of parameters:
•
Start frequency, i.e., frequency at the start of the actuation burst [20
𝑡𝑜
90
𝑘𝐻𝑧
]
•
End frequency, i.e., frequency at the end of the actuation burst [20
𝑡𝑜
90
𝑘𝐻𝑧
]
•
Number of pulses, i.e., number of cycles in the actuation burst [1
𝑡𝑜
12
𝑝𝑢𝑙𝑠𝑒𝑠
]
•
Pulse repetition time (PRT), i.e., the time interval between the start of one pulse and the start of the
next one [3
𝑡𝑜
500
𝑚𝑠
]
The effect of the above parameters is illustrated in Figure 12.
