Determination of Interference Levels
Abstract
The problem consisted in determining relative levels at which interfering radio-code and radio-phone signals would just preclude 100 percent intelligibility of the desired phone or code signal. It is desirable to determine at what level a code signal may be copied 100 percent intelligible by free-hand or pencil copy, and to what level the signal must be raised when a standard Navy typewriter is substituted for the "still" or pencil copy. The data summarized in tabular form in Table 8 are recapitulated below: (a) An interfering voice may be about 2.0 decibels above a desired voice for a workable circuit, and it should be not more than 5.4 decibels below the desired voice for a good circuit (one voice baritone and the other tenor). (b) An interfering voice may be about 10.4 decibels above a desired code signal for a workable circuit, and it should be not more than 5 decibels above the desired code signal for a good circuit (baritone voice and 1000 cycle code signal). (c) An interfering code signal may be about 6.6 decibels above a desired voice for a workable circuit, and it should be about 4.4 decibels below the desired voice for a good circuit. (d) An interfering code signal may be about 8 decibels above a desired code signal for a workable circuit, and about 3.5 decibels above the desired signal for a good circuit (one code signal frequency 1000 cycles, and the other 800 cycles).
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 07, 1939
- Accession Number
- AD1158818
Entities
People
- Ward E. Bower
Organizations
- United States Naval Research Laboratory