Abstract-Instantaneous frequency measurement receivers are a well-established technology that is used for the ultrafast characterization of pulsed microwave signals over a broad bandwidth. Recently, numerous photonic approaches to instantaneous frequency measurement (IFM) have been proposed and experimentally demonstrated, with the ultimate aim of leveraging the benefits of optical technology to improve the performance of already existent electronic solutions. Despite the numerous results, not so much attention has been paid so far to understand the subtle implications that system imperfections can have on realistic photonics-based IFM receivers. Here, we focus our attention in one of the most promising among these IFM techniques, which is based in optical power monitoring of a dual-sideband suppressedcarrier modulation after a Mach-Zehnder interferometer (MZI) filter. We develop a time domain model for the rigorous analysis of all major optical and electrical effects, including amplitude imbalance and phase errors in the modulator and the MZI, as well as on-pulse RF phase/frequency modulation. Simulations are then used to illustrate the substantial effect that a non-perfectly suppressed optical carrier can have on system performance. More importantly, it is shown that in a non-ideal situation the system amplitude comparison function critically depends with input RF power, thus greatly limiting the dynamic range of the photonicsbased receiver. Some approaches to solve these issues are also discussed.