This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for setting a resolution for an analog-to-digital converter (ADC) of a user equipment (UE) based on a modulated reference signal received from a base station (BS) during a first (for example, initial) symbol period of a slot. In one aspect, the first symbol period of the slot and a cyclic prefix (CP) of the first symbol period may be relatively longer in time than other symbol periods and other CPs of the slot and, in some implementations, the BS may transmit a configuration to the UE allocating a portion of the first symbol period for the transmission of the modulated reference signal. The UE may demodulate the modulated reference signal, calibrate an automatic gain control (AGC) of the UE, and set the resolution of the ADC of the UE based on the modulated reference signal.