An SDR receiver is overloaded when input signals exceed what level?

In a Software Defined Radio (SDR), the heart of the receiver is the Analog-to-Digital Converter (ADC). The ADC works by comparing the incoming analog RF signal voltage to a fixed internal reference voltage, converting those comparisons into digital numbers. If the incoming signal voltage exceeds this reference voltage, the ADC simply cannot measure it. It will output its absolute maximum digital value for any signal above the threshold, causing hard clipping and severe signal distortion. This condition is known as ADC overload. While the ADC will reach its 'maximum count value' during an overload, the actual physical cause of the overload is the input signal exceeding the hardware's reference voltage. Distractors mentioning sample rate and buffer sizes are incorrect because those parameters determine the frequency range and processing timing of the SDR, not its signal amplitude limit.