Digital AGC Gain Shifting for Overflow-Safe Feedback Control
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Solution Overview
Problem
Conventional digital feedback control systems face bit overflow issues when dealing with reference input values of varying magnitudes, leading to inaccurate deviation calculations and impaired feedback control responsiveness.
Innovation Solution
A digital AGC control method that involves storing reference and measured values in registers, detecting consecutive zero bits, and shifting the deviation value left by a corresponding number of bits to generate a setting value, thereby adjusting the number of significant digits and preventing bit overflow, while also converting negative values to positive for accurate calculation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional digital feedback control is used without range switching, then device complexity is reduced, but bit overflow occurs leading to measurement precision loss
Solution Approach 1:
The patent applies dynamics by making the gain of the feedback control system variable rather than fixed. The gain is dynamically adjusted based on the magnitude of the reference input value, allowing the system to adapt to different input ranges and prevent bit overflow while maintaining measurement precision.
Solution Approach 2:
The patent changes the gain parameter of the feedback control system based on the magnitude of the reference input value. By detecting the number of leading zero bits and adjusting the gain accordingly, the system prevents bit overflow in deviation calculations while maintaining accuracy across different input magnitudes.
2Measurement precision
If range switching is implemented to prevent bit overflow, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent extracts the gain adjustment function from a complex range switching mechanism and implements it directly in the feedback control unit. By detecting leading zero bits and applying corresponding gain multiplication, the system achieves range adaptation without requiring separate range switching hardware or complex structural changes.
Solution Approach 2:
The patent makes the feedback control unit multi-functional by enabling it to both detect the magnitude of reference input values and automatically adjust its gain accordingly. This universal approach eliminates the need for separate range switching units, simplifying the overall system structure while maintaining measurement precision.
3Device complexity
If fixed gain is used in feedback control, then device complexity is reduced, but feedback control responsiveness deteriorates for varying input magnitudes
Solution Approach 1:
The patent applies dynamics by making the feedback control gain variable rather than fixed. The gain is dynamically adjusted based on the magnitude of the reference input value, allowing the system to respond appropriately to different input scales and maintain optimal responsiveness across varying operating conditions.
4Speed
If automatic gain adjustment is implemented, then feedback control responsiveness is improved, but device complexity increases
Solution Approach 1:
The patent extracts the gain adjustment function from a complex automatic gain control mechanism and implements it directly in the feedback control unit. By detecting leading zero bits and applying corresponding gain multiplication, the system achieves automatic gain adjustment with minimal additional complexity.
Data Source
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AI summary
A digital AGC control method and feedback control apparatus that enable appropriate feedback control in response to reference input values of various magnitudes are provided. The method comprises a first step in which a digital AGC unit 11 outputs a setting value in accordance with a reference input value, a second step in which a PI control unit 12 calculates an operation amount of a controlled object 16 using the setting value, a third step in which a DAC 13 generates an output signal Y representing the operation amount, a fourth step in which a gain regulator 14 and an ADC 15 calculate a measurement value M of the controlled object; and a fifth step in which the measured value M is input to the digital AGC unit 11, said first step storing the reference input value X in a first register, storing the measured value M input in the fifth step in a second register, calculating and storing in a third register a deviation between the reference input value X and the measured value M, detecting a number of consecutive bits, other than a sign bit, of "0" value on the higher-order bit side of the first register, shifting the third register left in accordance with this number of bits, and generating a deviation setting value as the setting value.