The Model 4200 is a microprocessor-based solid state RF microwattmeter. The instrument is capable of measuring RF power levels from 1 nW (-60 dBm) to 1W (+30 dBm) for a frequency range of 0.2 MHz to 110 GHz. The instruments calibrated power level and frequency range is determined by the Series 4200 sensor used with the instrument. The Series 4200 sensors are accessories and must be ordered per application. Refer to Table 1-2 for the Series 4200 sensor characteristics. 1-5. The Model 4200 is designed to perform the following operations: a. Low-power transmitter, signal generator, and oscillator measurements. b. SWR and return-loss measurements with directional couplers and slotted lines. c. Gain and insertion loss measurements. d. RF attenuation and SWR measurements. e. Antenna measurements. 1-6. The Model 4200 design features are as follows: a. Wide Frequency Range. 0.2 MHz to 110 GHz. The calibrated frequency range of the instrument is determined by the sensor utilized. Refer to Table 1-2. b. Wide Power Range. Depending on the selected sensor. the instrument will measure RF power from I nW up to IW. Temporary overloads up to 300 mW with Series 4200-4 sensors and up to 2W with Series 4200-5 sensors will do nn permanent harm to the instrument or the sensor. When measuring pulsed signals, the power indications are accurate up to 20 microwatts peak power (200 microwatts with Se-ries 4200-5 sensors). External attenuators may be used to extend the measurement range of the instrument. c. Low Noise, The instrument has' been designed and constructed to minimize noise from all sources. The sensor cable is of a special low-noise design; vigorous flexing causes only momentary minor deflections on the most sensitive range of the instrument. The sensors are insensitive to shock and vibration; even sharp tapping on the sensor barrel causes no visible deflection on any range. Internal signal amplification occurs at approximately 94 Hz, thereby reducing susceptibility to 50 or 60 Hz fields. A low-noise solid-state chopper is used. d. LED Display. Measured power levels are displayed by a 4 digit. LED type readout with decimal points and minus sign. Annunciators associated with the LED display indicate the units of measurement. The resuit is a clear, unambiguous readout that minimizes the possibility of misinterpretation. The display is also used to show data being entered into non-volatile memory and to display data recalled from non-volatile memory; the display and annunciators blink on and off during data entry and recall to indicate that displayed values are not measured values. e. Analog Indications. A front-panel analog meter provides relative power' indications for peaking or nulling applications. A dc voltage proportional to the measured power level is available at a rear-panel connector for application to a recorder or other external device. f. Pushbutton Measurement Mode Selection. A choice of measurement modes is available to the operator. Indications in terms of power or d Bm can be selected by pressing the appropriate front-panel key switch. A dB reference level can be entered through the keyboard and a display mode selected to indicate power levels in dB. relative to a dB reference level. g. Automatic Ranging. Autoranging under control of the microprocessor eliminates the need for manual ranging. Alternately, a measurement range can be retained for all measurements, if desired, by selecting the range hold mode. Applications of power levels that exceed the maximum or minimum measurement capability of the instrument (or range in the hoid mode) results in an error indication on the LED display. fi. Automatic Zeroing. An automatic zeroing circuit eliminates the need for tedious, often inaccurate, manual zeroing. With zero input to the sensor, pressing a front- panel key switch directs the microprocessor to compute and store zero corrections for each range, and the instrument is thereafter corrected on each range in accordance with the stored data. This method is considerably simpler, faster, and more accurate than manual zeroing. i. Automatic Sensor Compensation. Calibration factors for up to eight sensors may be stored in the microprocessor. Calibration data is written into non-volatile storage at the factory for sensors ordered with the instrument; calibration data may also be written into storage in the field. When the sensor being used and the measurement frequency are specified through front-panel keyboard entry, measurement values are corrected automatically with calibration factors. Alternately, the calibration factor in dB for a particular sensor being used may be entered through the keyboard, and the measurement values are then corrected a utomatically in accordance with the correction factor. Both power and dB values are corrected. j. Built-in Power Reference. An accurate. 1.000 milliwatt. 50 MHz signal for instrument calibration is provided by ¿i built-in power reference. Calibration is simpiv a matter of connecting the sensor to the power reference, and pressing a key: the calibration correction is computed automatically by the microprocessor. The calibration circuit has built-in protection against inadvertent key actuation when the sensor is not connected to the power reference: calibration correction is limited to approximately 7.59Í from the original factory set value. Computed calibration corrections that exceed this range are rejected automatically, and the instrument returns to its previous sensitivity. If the instrument is supplied with a 75-ohm sensor (4200-4C). an adapter (P/N 950006) is also supplied. This adapter is used between the power reference and the sensor to convert the Type N power reference connector to a 75-ohm Type N. Before calibration, a 0.17 dB CAL FACTOR should be entered to compensate for the mismatch error that is introduced by the 75-ohm sensor. • k. Pushbutton High/Low dB Limit Selection. High low dB limits may be entered through the front-panel keyboard. A front-panel annunciator indicates when measured d B levels are outside the preset limits. Signals are also activated at a rear-panel connector to provide remote indications of out-of-limit measurements. 1. Soiid-state Chopper. Signal amplification in the instrument occurs at approximately 94 Hz. Input signals from the sensor are converted into a 94 Hz signal by a solid-state, low-level input modulator (chopper), which represents a distinct improvement over electromechanical choppers. Extended service life is assured through the elimination of contact wear, contamination, and other problems associated with electromechanical choppers. m. Signature Analysis Maintenance. Connection facilities to permit signature analysis maintenance are incorporated. Digital circuit troubles can be localized rapidly and accurately using the signature analysis maintenance tech- nique.-thereby reducing instrument down-time. A diagnostic ROM (P/N 961003) is available from Boonton Electronics Corporation for signature analysis maintenance.