A signal processing system comprising: a measurement apparatus that measures current and voltage which are supplied to a plurality of electric devices from a power supply; and a processing apparatus that is connected to the measurement apparatus through a communication channel and estimates operation conditions of the respective electric devices from a measurement result of the measurement apparatus, wherein the measurement apparatus includes a detection unit that detects analog waveform data of the current and the voltage which are supplied to the electric device, a conversion unit that samples the analog waveform data detected by the detection unit on the basis of a predetermined sampling frequency and converts the sampled analog waveform data into digital waveform data, and a transmission unit that transmits the digital waveform data to the processing apparatus, wherein the processing apparatus includes a reception unit that receives the digital waveform data transmitted from the transmission unit, a storage unit that stores the digital waveform data received by the reception unit, a separation unit that separates the digital waveform data stored in the storage unit into pieces of digital waveform data for the respective electric devices, and an operation estimation unit that analyzes the pieces of digital waveform data separated by the separation unit and estimates the operation conditions of the respective electric devices, wherein the conversion unit converts the analog waveform data into the digital waveform data by a predetermined number of samples including three zero-cross points, and stops the conversion until a predetermined period of time elapses when the conversion is terminated, and wherein the predetermined number of samples is the number of samples which is obtained by adding the number of samples corresponding to a maximum frequency variation of the analog waveform data to the number of samples for one cycle of the analog waveform data. a measurement apparatus that measures current and voltage which are supplied to a plurality of electric devices from a power supply; and a processing apparatus that is connected to the measurement apparatus through a communication channel and estimates operation conditions of the respective electric devices from a measurement result of the measurement apparatus, wherein the measurement apparatus includes a detection unit that detects analog waveform data of the current and the voltage which are supplied to the electric device, a conversion unit that samples the analog waveform data detected by the detection unit on the basis of a predetermined sampling frequency and converts the sampled analog waveform data into digital waveform data, and a transmission unit that transmits the digital waveform data to the processing apparatus, wherein the processing apparatus includes a reception unit that receives the digital waveform data transmitted from the transmission unit, a storage unit that stores the digital waveform data received by the reception unit, a separation unit that separates the digital waveform data stored in the storage unit into pieces of digital waveform data for the respective electric devices, and an operation estimation unit that analyzes the pieces of digital waveform data separated by the separation unit and estimates the operation conditions of the respective electric devices, wherein the conversion unit converts the analog waveform data into the digital waveform data by a predetermined number of samples including three zero-cross points, and stops the conversion until a predetermined period of time elapses when the conversion is terminated, and wherein the predetermined number of samples is the number of samples which is obtained by adding the number of samples corresponding to a maximum frequency variation of the analog waveform data to the number of samples for one cycle of the analog waveform data.