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Применения > > Dual-Channel Colorimeter with Programmable Gain Transimpedance Amplifiers and Digital Synchronous Detection

Dual-Channel Colorimeter with Programmable Gain Transimpedance Amplifiers and Digital Synchronous Detection (CN0363)

The circuit shown in Figure 1 is a dual-channel colorimeter featuring a modulated light source transmitter, programmable gain transimpedance amplifiers on each channel, and a very low noise, 24-bit Σ-Δ analog-to-digital converter (ADC). The output of the ADC connects to a standard FPGA mezzanine card. The FPGA takes the sampled data from the ADC and implements a synchronous detection algorithm.


Figure 1. Dual-Channel Colorimeter with Programmable Gain Transimpedance Amplifiers and Lock-In Amplifiers(Simplified Schematic: All Connections and Decoupling Not Shown)

By using modulated light and digital synchronous detection rather than a constant (dc) source, the system strongly rejects any noise sources at frequencies other than the modulation frequency, providing excellent accuracy.

The dual-channel circuit measures the ratio of light absorbed by the liquids in the sample and reference containers at three different wavelengths. This measurement forms the basis of many chemical analysis and environmental monitoring instruments used to measure concentrations and characterize materials through absorption spectroscopy.

Возможности

  • Dual channel RGB colorimeter 
  • High sensitivity low noise transimpedance amplifier 
  • Programmable gain TIA 
  • Digital synchronous detection

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Dual-Channel Colorimeter with Programmable Gain Transimpedance Amplifiers and Digital Synchronous Detection  CN0363

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