DEVELOPMENT OF LINEAR POWER TUBES.
Abstract
Tests were performed on the modified 4CX5000 (X552) and the modified 4CX3000 (X784) as well as on the EIMAC standard production 4CX5000R and the 5CX3000A. A 5000 watt tetrode with auxiliary electrode (X552-P), a 5000 watt pentode with auxiliary electrode (X552-R), and a 3000 watt pentode with auxiliary electrode (X784-N) were tested using a variety of DC auxiliary electrode voltages as well as combinations of DC suppressor voltages. The results of tests indicate that a DC voltage on the auxiliary electrode will cause a change in the intermodulation distortion characteristics. The pentode models with auxiliary electrodes gave the most encouraging results. From zero to 4500 watts PEP, a third order intermodulation distortion of -45 db and a fifth order intermodulation distortion of -50 db can be expected. However, at 5000 watts PEP the distortion becomes worse. When a saturated (non-linear) RF drive voltage is applied to the auxiliary electrode in phase with the grid drive voltage, the distortion at optimum operating conditions is -50 db from zero to 5000 watts PEP. Attempts were made to use other methods in tube design to improve linearity. The EIMAC 5CX3000A (standard production) was tested and gave satisfactory results; however, at the 5000 watt PEP level, the fifth order intermodulation distortion level does not meet the proposed -50 db goal. An experimental pentode of the 5000 watt type was built. The test results indicate -45 db third order and -50 db fifth order intermodulation distortion from zero to 5000 watts PEP. An increased range of operating parameters (over the 5CX3000A) is available with the 5000 watt pentode. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 15, 1967
- Accession Number
- AD0663167
Entities
People
- Gordon E. Liljegren
- William H. Sain