FEATURES The TF 1 370A is a general-purpose sine wave generator covering the frequency range 10 c/s to 10 Me/s. It also delivers a high-quality square wave output at frequencies between 10 c/s and 100 kc/s. The instrument is primarily a signal source for measurements and tests on audio and video amplifiers and networks. With its four output impedances - 600, 130, 100, and 75 n - it is suitable for use with transmission linesj filtersj attenuators, etc. Among other applications as a sine wave generator is that of providing the excitation voltage for a.f. and r.f. bridges. And the quality of the square wave output also renders the instrument particularly effective for such purposes as rapid testing of audio amplifier bandwidth. The signal originates in a Wien bridge oscillator covering 10 c/ s to 10 Me/ s in six decade bands, the top band extending from 1 to 10 Me/s. A single scale is used for the four lower bands and separate scales for the two upper bands; this gives a total scale length of 105 inches and makes a 1% change in frequency easily discernible. TF 1370AR is a rack-mounting version of the TF 1370A and is supplied, complete with dust cover, for mounting in a standard 1 9 inch rack.