Browse Prior Art Database

Forming an all Lower, or Upper, Sideband Group

IP.com Disclosure Number: IPCOM000094373D
Original Publication Date: 1966-Oct-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 3 page(s) / 98K

Publishing Venue

IBM

Related People

Thrasher, PM: AUTHOR [+2]

Abstract

This system is different from the integrated frequency-division multiplexing, time-division switching system disclosed in the IBM Journal of Research and Development, Vol. 9, No. 2, pp. 137-40, March, 1965. That system is shown at A and operates as explained in the publication. There are twelve local lines in and out, 1A...12A and 1D...12D, respectively. Lowpass filters 1J...12J and 1K...12K have pass bands from 0 to 4 kc. Bandpass filters IL...12L and 1M...12M have adjacent 4 kc pass bands as indicated in the drawing. Output sampling switches 1C...12C and 1G...12G close in fixed order. Input switches 1B...12B and 1F...12F close in an order dictated by the desired connections. The sampling rate is fs = 8 kc. Generalized resonant transfer is included as part of the switching process between filters.

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Forming an all Lower, or Upper, Sideband Group

This system is different from the integrated frequency-division multiplexing, time-division switching system disclosed in the IBM Journal of Research and Development, Vol. 9, No. 2, pp. 137-40, March, 1965. That system is shown at A and operates as explained in the publication. There are twelve local lines in and out, 1A...12A and 1D...12D, respectively. Lowpass filters 1J...12J and 1K...12K have pass bands from 0 to 4 kc. Bandpass filters IL...12L and 1M...12M have adjacent 4 kc pass bands as indicated in the drawing. Output sampling switches 1C...12C and 1G...12G close in fixed order. Input switches 1B...12B and 1F...12F close in an order dictated by the desired connections. The sampling rate is fs = 8 kc. Generalized resonant transfer is included as part of the switching process between filters. The twelve trunk channels in the region from 60 kc to 108 kc in 4 kc increments are formed in one modulation step from the baseband. The modulated baseband signals are translated along the frequency axis into an array of upper and lower sideband signals as shown at B. Such is for the situation in which all local lines 1A...12A are switched out to the trunk channels 1H...12H in the order 1B to 1G, 2B to 2G,... 12B to 12G.

The difference in this system is the forming of all lower sideband group signal output shown at C, as distinguished from the upper and lower sideband group signal output shown at B. This system also employs generalized resonant transfer as part of the switching process between filters. This system is shown at
D. Lowpass filters 1W...12W and 1X...12X have pass bands from 0 to 4 kc. Bandpass filters 1Y...12Y and 1Z...12Z have adjacent 4 kc pass bands as indicated. The all-lower sideband group is formed by using two modulation steps for odd-numbered bandpass filters and one modulation step for the others. On the output trunk group side, filters 1Z, 3Z,... 11Z have their outputs combined and connected to low-pass filter 13Z having a pass band from 0 t...