What does apdUpperThreshPeakExceededCnt actually count?

Question

Hello, 
 
 As per the title, what exactly does apdUpperThreshPeakExceededCnt / apdLowerThreshPeakExceededCnt actually count? 
 Is it samples? 
 Is it local maxima? 
 Are the peaks counted on the instantaneous power of the received signal or on the on the received signal amplitude? 
 
 Thank you in advance. 
 
 K.

RahulMushini · Accepted Answer

Automatic Gain Control (AGC) has two modes of operation 
 
 Normal Mode 
 Fast Attack Mode 
 
 Note: Assume the clock counter limit is 8 clock cycle. 
 Normal Mode: 
 
 Figure 1: Normal Mode 
 Figure 1 illustrates the operation of the Normal mode AGC. During the first period, when the signal's peak power exceeds the threshold, the AGC clock counter begins counting. At some point within the first period (indicated in green), the AGC clock counter exceeds the required number of clock cycles. At the end of the first period, the attenuation levels are applied, reducing the signal's power below the threshold, and simultaneously, the AGC clock counter resets. 
 In the second period, the signal again crosses the threshold, causing the AGC counter to start counting the clock cycles. However, before the counter exceeds the required number of cycles, the signal&rsquo;s power drops below the threshold. Since the AGC counter doesn&rsquo;t reach the necessary count, the attenuation is not triggered, and by the end of the second period, the AGC counter resets. 
 Note: The 1 st and 2 nd periods are the gain update period which is set by the user in TES. 
 Fast Attack Mode: 
 
 Figure 2: Fast Attack Mode 
 In this case, the key difference is when the attenuation is applied. During the first period, the signal exceeds the threshold, causing the AGC clock counter to surpass the clock cycle limit, triggering the attenuation immediately and resets the AGC counter. At the end of the first period, again AGC counter resets. 
 In the second period, the signal once again exceeds the threshold, and the AGC clock counter reaches 4 clock cycles before the signal falls back below the threshold. After some time within the same period, the signal power rises above the threshold again, and the AGC clock counter continues counting, now reaching 10 clock cycles. This exceeds the AGC clock counter limit, triggering the attenuation. Here the AGC clock counter resets once the attenuation is triggered to take care of the situation where signal peak power goes above the threshold again within the same period as shown in the figure 2. 
 Regards 
 Rahul)

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What does apdUpperThreshPeakExceededCnt actually count?