Showing papers on "Spectrogram published in 1968"

Modulation in bird sounds

Abstract: Yet these complexities are useful not only in the study of the patterns themselves, but also for interpreting the functional anatomy of the sound producing structures, the nature of the message, and the relationships among the birds involved. This paper analyzes several bird vocalizations and interprets their patterns as the product of individual and interacting oscillators and sound modifying structures; it also suggests a model for the operation of the syrinx during sound production. To determine some of the variation and complexity in bird vocalizations I made sound spectrograms and oscillograms of song phrases sampled from the records produced by Kellogg and Allen (1959, 1962). These spectrograms indicated that the most complex fundamentals were similar to electronically produced modulations. Such modulations are easily recognized by their audible "buzzy" quality. On the spectrograms time is indicated on the horizontal axis, frequency on the vertical one. The horizontal line on some spectrograms indicates that portion of the signal shown on the corresponding oscillogram. On oscillograms time is indicated on the horizontal axis and the instantaneous relative amplitude of the sound wave on the vertical one. Some bird vocalizations are simple, in that their fundamentals are analogous to signals produced electronically by a single sine-wave oscillator. Up-slurs and down-slurs are simple changes in frequency. Other sounds are mixtures of two such independent signals. The most complex sounds discussed in this paper are amplitude-modulated (AM) and frequency-modulated (FM) signals, particular interactions between two independent oscillations and analogous to radio broadcasting waves. Explanations of the nature of such waves may be found in the Radio amateur's kandbook (Amateur Radio Relay League, 1960). In essence, AM and FM are complex waves, the shapes of which are

Frequency spectrum analyzer with displayable colored shiftable frequency spectrogram

Abstract: Sound signal is analyzed so that there are provided a plurality of different constituent frequency components by means of a set of band-pass filters, and the thus analyzed frequency components are time-sequentially supplied to a color display which employs a color picture tube and its associate circuits for displaying different colors representative of the intensities of the frequency components.

Measurement and identification of laboratory-produced vacuum ultraviolet spectral lines.

Abstract: : Spectral lines of carbon, nitrogen, oxygen, and silicon have been measured and identified on spectrograms obtained from a large theta-pinch plasma device. The first spectrogram, a time-integrated exposure at grazing incidence, covered the region from 15 to 210A. Wavelengths of approximately 350 spectral lines were determined with a maximum error of 0.008A between 15A and 130A and with a maximum error of 0.015A for the remainder of the spectrogram (due to a lack of suitable standard lines). The region from 350A to 1800A was photographed in two sections: 350A to 1050A, and 950A to 1800A. Approximately 100 lines were measured and identified. The wavelengths for the grazing incidence spectrogram were calculated by means of a computer program, written in Fortran IV, which is given together with a detailed explanation of its use. (Author)