The Model CE-7 Multi-Channel FM Communications Monitor is designed to measure the frequency and frequency-modulation deviation of transmitters and other signal sources. The CE-7 is crystal controlled and can operate on any one of 23 frequencies between 20 MHz and 1150 MHz. Which frequencies are assigned to the 23 positions is specified by the customer. Any number of crystals between one and 23 may be selected and the operation of the instrument is not compromised if only one or two crystals are installed. The Cushman Model MCO-6 Multi-Channel Oscillator (accessory) offers an additional 23 frequencies should the need for other crystal frequencies arise. The CE-7 can also generate FM and CW signals within the frequency limits stated above. The output level of the generated signal may be adjusted from 0. 1 to 100 microvolts and provides the capability of determining the sensitivity of FM communication receivers. Signal generation of up to ten optional crystal-controlled IF frequencies is available between 250 kHz and 13. 5 MHz. The output levels of the IF signals are continuously variable. The CE-7 must operate with either a Model 301 Oscilloscope or a Model 302 FM Deviation Meter inserted into the left-hand plug-in cavity, and a Model 303 Broadband Mixer or one of the RF plug-ins inserted into the right-hand plug-in cavity. The combination of the plug-ins is at the discretion of the customer.