INTRODUCTION The Model 203A is an all solid-state, rack mounting distribution amplifier. The unit accepts three input frequencies and provides 12 output signals, four signals at each input frequency. The Model 203A is completely modular in construction. All preamplifiers and amplifiers are contained on plug-in printed circuit boards. Each printed circuit board may be easily removed and exchanged for rapid servicing. Further, printed circuit boards bearing the same part number are electrically and physically interchangeable. ELECTRICAL SPECIFICATIONS INPUT FREQUENCIES The distribution amplifier operates with sinewave inputs of 100 kHz, 1 MHz, and 5 MHz. Each input frequency must be within 1% of nominal value. INPUT LEVELS 0.5 to 5 0 volts rms for each input. A level adjustment for each input is provided on the rear panel. INPUT IMPEDANCE NominaUy 50 ohms with any number of amplifier modules connected. OUTPUTS There are usually four output channels at each of the three input frequencies. However, other output configurations are possible up to 12 outputs of one desired frequency; 100 kHz, 1 MHz or 5 MHz. OUTPUT LEVELS Each channel is continuously adjustable over the range of 0. 5 to 4. 0 volts rms into 50 ohms. Level controls for individual amplifiers are accessible through the top cover. STABILITY Typically better than 1 x 10"H standard deviation for a one second averaging time at 1 MHz. BANDWIDTH Less than 3% of input frequency for 3 db down and 15% for 30 db down. ISOLATION Under all conditions of system loading, isolation of the 100 kHz and 1 MHz signals from adjacent channels is 80 db below full output. Isolation of the 5 MHz signal from adjacent channels is at least 65 db below full output. OUTPUT VARIATIONS A change in load conditions on any channel from open-circuit to short-circuit causes less than 3% change in the signal level of any other channel. METERING Front panel meter and switch provides indication of intermediate and output signal levels, and power supply voltage. SPURIOUS AU non-harmonically related signals generated by the amplifier are 80 db below the output level of any channel. HARMONIC DISTORTION Harmonic distortion generated by the distribution system is 60 db below the output level of any channel. DUTY CYCLE The distribution amplifier is designed for continuous operation throughout its service life without degradation of specified performance. POWER REQUIREMENTS 115/230 volts ac ±10%, 50 to 400 Hz, approximately 35 watts. A separate connector on the rear panel may be used to connect standby dc power from 22 to 30 vdc. Internal circuitry detects loss of primary power and automatically cuts over to the external standby dc power.