Agilent 1961-09 free download

File name 1961-09.pdf

HEWLETT-PACKARD JOURNAL T E C H N I C A L I N F O R M A T I O N F R O M T H E - d p - L A B O R A T O R I E S JLISHED BY THE HEWLETT-PACKARD COMPANY, 1501 PAGE MILL ROAD, PALO ALTO, CALIFORNIA SEPT. -OCT., 1961 A New SWR Meter with High Gain-Stability ONE of the important instruments in the micro heretofore but also increase the suitability of this wave measurement area is basically an audio type of instrument for rf attenuation measurements. frequency instrument known as a Standing Wave The new instrument is tunable over a 5% range so Indicator or SWR Meter. This instrument is essen as to accommodate the tolerances and drift that are tially a very high gain (» 100 db) audio amplifier often encountered in modulating frequency. At the which is tuned to achieve high selectivity and which same time it has a selectivity that is variable from 15 has an output meter calibrated for standing-wave to 100 cps to meet a variety of measurement condi work. Although the instrument was originally in tions varying from highest discrimination against tended for use with a slotted line section to measure noise to fast amplitude response for swept-frequency vswr, it has seen increasing importance in micro measurements. wave attenuation measurements using audio substi For attenuation-measuring situations, the instru tution techniques. It is calibrated for and normally ment is further designed to give high and constant used with a square-law rf detector, but its high sensi resolution over its complete measurement range. This tivity and single acceptance frequency also make it is achieved by arranging for each 2.5-db section of valuable as a detector for audio frequency bridges. the normal 10 db meter scale to be expanded to oc A new SWR Meter has now been designed which cupy a full meter scale length and one that is roughly incorporates advances that not only make vswr meas linear for high readability. The arrangement is such urements easier and more accurate to perform than that 31.5 db of attenuation can be measur