DE1041092B - Carrier frequency system for four speech channels - Google Patents

Description

GERMAN

The invention relates to a carrier frequency system for four speech paths with a channel width of 4 kHz, which can be used both for the transmission of individual communication channels in two-wire operation (EK) and as a two-wire Getremitlagesystem (Z4) or four-wire equalization system.

Carrier frequency systems for each of these three modes of operation are already known, however these known carrier frequency systems do not have a uniform system structure, but are in each case developed only according to the design principles relevant for the operating mode in question; let them therefore not without essential and fundamental changes and especially not without additional ones Use effort for another operating mode.

However, the invention is based on the object of building a carrier frequency system so that it is without noteworthy changes and without additional effort, optionally in each of the three above Modes of operation can be operated.

This object is achieved according to the invention by means of a frequency plan in which two channels of the one transmission direction and two channels of the other transmission direction (EK system) or four channels of the same transmission direction (Z4 or F4 system) and are lined up without gaps.

By combining four individual channels each into seamless transmission groups, it is possible to use the system optionally for all three operating modes without additional effort; included In this system the corresponding channels are in the same transmission layers in all operating modes, are also always in each operating mode all existing channel band filters are used and no additional filters are required for other frequency ranges.

If, in single-channel operation, the adjacent individual channels belonging to a speech path are to be in opposite frequency positions for the two transmission directions (normal position or inverted position), channels 4 ... 8, 12 ... 16, 24 ... 28, 32 ... . 36 kHz in one frequency position (normal position or inverted position) and channels 8 ... 12, 16 ... 20, 28 ... 32, 36 ... 40 kHz in the other frequency position (inverted position or normal position) be built up, while for two-wire separate position operation (Z4) and four-wire equal position operation (VA) the channels of one transmission group (4 ... 20 kHz) in one frequency position, z. B. control position, and the channels of the other transmission group (24 ... 40 kHz) in the other frequency position, z. B. upside down, must be built up.

Carrier frequency system for four speech paths

Applicant:

Feiten & Guilleaume

Telecommunication systems G. m. B. H.,

Nuremberg,
Outer Bayreuther Strasse / Bierweg 180

DipL-Ing. Helmut Sippel, Nuremberg,
Has been named as the inventor

However, in the case of single-channel operation, the adjacent channels of a speech path may be the same Frequency position (normal position or inverted position), there is no need to set up the channels for Single channel operation; the carrier-frequency structure of the system is then uniform for all three operating modes, according to the structure required for two-wire separation operation.

Single-channel operation and two-wire separation operation then only differ in terms of the low-frequency occupancy of the individual transmission channels with the corresponding message (voice frequency) Ribbons.

In both cases, the transmission group B (24 ... 40 kHz) for the opposite direction in two-wire separate position operation - in a known manner - can also be obtained by converting the transmission group A (4 ... 20 kHz) with the frequency 44 kHz .

Since each channel is assigned its own transmit or receive amplifier for single-channel operation must, no group amplifiers and the channel amplifiers are provided in the system according to the invention arranged in front of the transmission direction and behind the channel band filters in the reception direction. From this it follows the advantage that the channel band filter, which according to a further feature of the invention at the same time are designed as directional filter, can be connected directly in parallel. as further advantages also result in a particularly favorable design of the amplifier when used of transistors with regard to the low modulation limit as well as significantly lower distortion

809 658/292

ments compared to an arrangement with common group amplifiers. In a system setup with alternately The channel band filters must have an attenuation curve that is symmetrical to the center of the channel the same channels for single-channel operation on the one hand and for two-wire and four-wire operation on the other lie in opposite frequency positions.

In the case of a system structure with uniform frequency positions of the individual channels for the three different ones Operating modes, this special measure is not required.

In the drawing are the frequency plans of two systems according to the invention for the different ones Operating modes shown:

1 shows a system in which, in single-channel operation, the adjacent channels of a speech path are in different frequency positions - namely in the normal position for the direction AB and in the inverted position for the direction BA ; In this case, the conversion of the individual voice bands into the transmission layers 4 ... 8, 8 ... 12, 12 ... 16, 16 ... 20 kHz and 24 ... 28, 28 ... 32, 32 ... 36, 36 ... 40 kHz requires the carrier frequencies 4, 12, 20 and 24, 32, 40 kHz; If the channels are set up in the opposite frequency position - i.e. in the reverse position for the direction AB and in the normal position for the direction BA - only the carrier frequencies 8, 16 and 28, 36 are required for the implementation.

Fig. 2 shows the structure of a system in which the channels of a speech path in single-channel operation for Both directions of transmission in the same frequency position - in the normal position for the transmission positions 4 ... 20 kHz and in the inverted position for the transmission layers 24 ... 4OkHz; in this case will be to convert the voice bands into the transmission position the carrier frequencies 4, 8, 12, 16 and 28, 32, 36, 40 required; should the transmission groups in the reverse frequency positions - i.e. in the inverted position for the transmission layers 4 ... 20 kHz and in the normal position for the transmission layers 24 ... 40 kHz the carrier frequencies 8, 12, 16, 20 and 24, 28, 32, 36 kHz are required for implementation.

Fig. 3 shows the same system when used in two-wire separation mode; a comparison of FIGS. 2 and 3 shows that the difference between the two modes of operation (EK and Z4) with a completely identical structure in terms of frequency consists only in the occupancy of the individual transmission channels.

Fig. 4 shows the system when used in four-wire synchronous operation (V 4), in which the transmission group 24 ... 40 kHz is not required per se.

In the case of four-wire separation, the channel band filters that are only present once in each terminal are used for the transmission group 4 ... 20 kHz, but for both transmission directions - i.e. twice ·- needed. According to a further feature of the invention, however, one can use the incoming transmission group in each terminal with 44 kHz in the frequency position of the transmission group for the opposite direction convert 24 ... channel band filters of this transmission group that are present in themselves can be used at each terminal; This measure enables the otherwise required second channel band filter for the frequency range ... 20 kHz can be saved.

Claims (9)

- Patent claims: 1. Carrier frequency system for four speech paths with a channel bandwidth of 4 kHz, in which all channels are brought into the transmission position by direct conversion and which is used both for the transmission of individual X message channels in two-wire operation (EK) and as a two-wire separate position system (Z4j or four-wire Equal position system (F4; can be operated, characterized in that two channels of the one transmission direction and two channels of the other transmission direction (EK) or four channels of the same transmission direction (Z4 or Vi) ' to one or two for all three modes in Transmission groups located at the same frequency positions are combined and strung together without gaps. 2. Carrier frequency system according to claim 1, characterized in that the transmission groups are in the frequency positions 4 to 20 and 24 to 40 · kHz. - ■ 3. Carrier frequency system according to the claims 1 and 2, characterized in that channels 4 ... 8, 12 ... 16, 24 ... 28, 32 ... 36 kHz in the a frequency position, e.g. B. in normal position, and channels 8 ... 12, 16 ... 20, 28 ... 32, 36 ... 4OkHz in the other frequency position, e.g. B. are built upside down (single channel system). 4. Carrier frequency system according to claims 1 and 2, characterized in that the channels 4 ... 20 kHz in one frequency position, for. B. in the normal position, and the channels 24 ... 40 kHz in the other frequency position, z. B. in the upside-down position (two-wire separate layer and single channel system). 5. Carrier frequency system according to claims 1 and 2, characterized in that in four-wire synchronous operation for the purpose of utilizing the existing channel band filters for 24 ... 40 kHz, the transmission band 4 ... 20 kHz in the terminals in the receiving direction with 44 kHz is converted into the frequency position 24 ... 40 kHz. 6. Carrier frequency system according to one of claims 3 to 5, characterized in that each channel is assigned its own transmit or receive amplifier. 7. Carrier frequency system according to claim 6, characterized in that the channel amplifier in The transmission direction are arranged in front of and in the reception direction behind the channel band filters. 8. Carrier frequency system according to claims 6 and 7, characterized in that the channel band filter at the same time designed as a directional filter and connected directly in parallel. 9. Carrier frequency system according to claim 8, characterized in that the channel band filter one have a symmetrical attenuation curve in relation to the center of the duct. Considered publications:
W. Klein, carrier frequency technology, 1949, pp. 6 to 13, especially fig. 3 and 4. 1 sheet of drawings © 809 658 / 292-10.58