Measuring receiver

In telecommunication, a measuring receiver or measurement receiver is a calibrated laboratory-grade radio receiver designed to measure the characteristics of radio signals. The parameters of such receivers (tuning frequency, receiving bandwidth, gain) can usually be adjusted over a much wider range of values than is the case with other radio receivers. Their circuitry is optimized for stability and to enable calibration and reproducible results. Some measurement receivers also have especially robust input circuits that can survive brief impulses of more than 1000 V, as they can occur during measurements of radio signals on power lines and other conductors.
Applications.
Measuring receivers are used with calibrated antennas to
Measuring receivers are also used without antennas to
Measuring receivers are widely used in metrology and calibration lab environments, spectrum monitoring and electromagnetic-compatibility facilities.
Types.
Depending on the intended application area, several types of measuring receivers can be distinguished:
Some measuring receivers (such as Agilent’s N5531S and MXE or Rohde & Schwarz's FSMR and ESU) also include a signal analyzer, power meter, and a sensor module to allow the instruments to be used together or individually for general-purpose measurement tasks.
The time-domain EMI measurement systems show additional features like weighted spectrogram mode, oscilloscope mode as well as measurement of discontinuous disturbance according to CISPR 14-1.
Requirements for Compliance Testing.
Receivers that are used for compliance testing have to fulfill the basic emc standard CISPR 16-1-1. CISPR 16-1-1 defines requirements for indication of CW Signals and pulses. The amplitude range where these requirements are met is called CISPR indication range. Within this range the receiver can be used for compliance tests. Usually EMI receivers have a CISPR indication range that starts about 6dB above the noise floor. The performance usually demonstrated by a linearity check for sinusoidal signals and broadband pulses. This linearity check is performed over the amplitude range starting from typical levels of 10dBuV. Some EMI receivers, even if called full compliant have a CISPR indication range that starts at higher levels e.g. 40dBuV. Typically for such a receivers only one level e.g. 60dBuV is presented. A demonstration of CISPR compliance at lower levels cannot be demonstrated.