RU2182408C2 - Radio-electronic unit - Google Patents

Abstract

FIELD: radio electronics; receiving and processing signals arriving from satellite radio navigation systems. SUBSTANCE: small-sized radio-electronic unit built on single multilayer printed-circuit board has its printed-circuit board provided with six conducting layers; external layers carry printed-circuit conductors as well as electrical and radio components and internal layers accommodate conductors as well as bonded ground and power supply planes; interlayer connections are effected through metallized holes. Electrical and radio components and conductors are grouped in three sequential zones first one being used for analog conversion of satellite radio navigation system signals, second zone, for analog-to-digital conversion, and third zone, for digital conversion. Second layer has ground planes of all zones and third layer incorporates conductors for feeding first and second zones as well as additional conductors of third zone; fourth layer includes additional conductors of first and second zones and power supply plane of third zone; fifth layer has ground plane of first zone and additional conductors of second and third zones. Ground planes of second layer are interconnected by means of straight ground conductors arranged in accordance with location of signal conductors affording electrical communications among zones in external layers. First zone is surrounded over perimeter with shielding conductors arranged in opposition to each other in external layers. Shielding conductors of both external layers are coupled together and with ground planes of first zone (in second and fifth layers) be means of respective metallized holes. Shielding conductors have splits to pass signal conductors; non-split bonded sections of ground planes in second and fifth layers correspond to split sections. EFFECT: provision for eliminating stray pickups and induced noise unit implementing receiver-processor functions of satellite system. 5 cl, 9 dwg

Description

 The invention relates to radio electronics and can be used in the construction of electronic blocks that receive and process signals from satellite radio navigation systems (SRNS).

 A feature of the designs of electronic blocks that receive and process SRNS signals is the need to use heterogeneous functional units: analog microwave and high-frequency devices that implement the processes of receiving and converting SRNS signals, as well as various analog-digital and digital devices - correlators, synthesizers, synchronizers, processors realizing the processes of correlation search, tracking and digital processing of received signals [1, p. 112, fig. 47, p. 126, fig. 64]. Another feature is the varying degree of integration of electro-radio elements that implement these heterogeneous functions. For example, microcircuits of small, medium and high degree of integration can be used. In this regard, when combining within the framework of one, as a rule small-sized, design of such heterogeneous functional units and elements, which also work with signals substantially differing in frequency, the problem arises of ensuring their electromagnetic compatibility, eliminating mutual influence on each other and reducing level of spurious interference and induced interference.

 One of the well-known ways of constructing a solution to this problem is the development of a multi-block (multi-board) design, where on separate printed circuit boards are grouped electrical elements related to close (homogeneous) functional groups and processing signals similar in type and frequency, as, for example, in known designs [1 , from. 112, fig. 47], [2]. In this case, the problems of reducing spurious interference and induced interference can be solved by fairly simple technical means, based, for example, on board adaptation. However, this path is associated with an increase in the dimensions of the developed design.

 In those cases where dimensions are important, monoblock designs are developed in which heterogeneous functional units and elements are combined within the framework of a common structural element - a printed circuit board, such as, for example, in the radio-electronic block of the receiver-processor of SRNS signals described in [1, p. 132, fig. 69]. The problems arising in this case, associated with spurious pickups and induced noise, can be solved by well-known methods consisting in shielding individual functional units using appropriate metal screens.

 In addition, other useful design techniques can be used as additional measures to reduce spurious interference and induced interference, which include, in particular, installing additional external matching elements connecting the printed circuit board elements with the block case, as, for example, in [3], in a special arrangement of signal conductors on a printed circuit board, as, for example, in [4], [5, p. 112-115], in a special arrangement of earth conductors and power conductors, as, for example, in [5, p. 113-114]. At the same time, there is no solution to this problem that is common to all cases, and in each case, its own set of design tools is used to solve it, providing a solution to the problem under given specific conditions.

 As a prototype of the inventive radio-electronic unit, a well-known radio-electronic unit is described, described in [6, p. 258-261, fig. 12.2], which is a single-board design. The electronic block selected as a prototype contains a multilayer printed circuit board in which the interlayer connections of the printed conductors are carried out by means of metallized holes of the interlayer connections, in which the conductors, contact pads and radio-electronic elements are mounted in the outer conductive layers, and the remaining conductors are made in the inner conductive layers, as well as metallized earth and power planes with windows around metallized holes of interlayer joints, not connected data electrically with these planes. For example, in the case of a printed circuit board with ten conductive layers, the ground plane and the power plane are located in the fourth and fifth layers, respectively.

 Due to the indicated location of the ground and power planes in different conductive layers of the printed circuit board in the prototype unit, the problem of reducing spurious interference and induced interference is solved. Moreover, a successful solution to this problem is carried out under conditions when homogeneous electro-radio elements are used in the unit, and the processed signals are close in frequency, as, for example, in the case of a digital computer.

 The technical problem to which the claimed invention is directed is to eliminate constructive methods of spurious interference and induced interference in the conditions of a small-sized electronic block that implements the function of a receiver-processor of the SRNS and is performed on a single multilayer printed circuit board carrying heterogeneous (analog, analog-to-digital, digital) functional electro-radio elements of varying degrees of integration, and the frequency range of the signals processed and converted in the unit is from thousands of megahertz at the input to units of hertz at the output.

 The solution of this problem allows us to construct small-sized navigation receivers-processors based on the SRONS GLONASS and NAVSTAR signals on the existing elemental base.

 The essence of the invention lies in the fact that in a radio electronic unit containing a multilayer printed circuit board, in which the interlayer connections of the printed conductors are carried out by means of metallized holes of the interlayer connections, in which the conductors are made in the outer conductive layers, the contact pads are mounted and the radio electronic elements are mounted, and the inner conductive layers are made conductors and ground and power planes with windows around metallized holes of interlayer connections not electrically connected to these by planes, the radio-electronic elements and printed circuit boards of the board are grouped in three consecutive zones, the first of which corresponds to the zone of placement of radio-electronic elements performing analogue signal conversion of satellite radio navigation systems, the second to the zone of placement of radio-electronic elements performing analog-to-digital conversion of signals, and the third - to the zone of placement of radio-electronic elements digitally converting signals, and the electrical radio elements are mounted on a multilayer printed circuit board with six conductive layers, where low-frequency and high-frequency connectors are installed on the outer first conductive layer for connecting the electronic unit, respectively, to the power source and input signal, the ground plane of each of the zones is made in the inner second conductive layer, in the inner third conductive layer are made power conductors of the first and second zones and additional conductors of the third zone, in the inner fourth conductive layer additional the water conductors of the first and second zones and the power plane of the third zone, in the inner fifth conductive layer, the second earth plane of the first zone and additional conductors of the second and third zones are made, while the earth planes made in the inner second conductive layer are interconnected by direct earth communication conductors located in accordance with the location of the communication signal conductors, carrying out electrical communications between the zones in the outer first and sixth conductive layers of the board, the first zone is surrounded by to the meter with shielding conductors made against each other in the outer first and sixth conductive layers, said shielding conductors being connected to each other as well as to the ground planes of this zone in the inner second and fifth conductive layers by means of metallized openings of the interlayer connections formed therein to form a closed electrical circuit, these shielding conductors have gaps for the passage of the corresponding signal communication conductors, while the areas of gaps in the screen The conductive conductors in the outer first and sixth conductive layers correspond to solid metallized sections of the earth planes in the inner second and fifth conductive layers.

 In the inventive radio-electronic unit, the width of the earth communication conductors that connect the earth planes to each other in the inner second conductive layer is selected at least 1 mm.

 In the inventive radio-electronic unit, the conductors intended for shielding the corresponding signal communication conductor are located on both sides thereof and are connected to the earth planes through metallized holes of the interlayer connections made at least at the beginning and at the end of each of the conductors with the formation of a closed electrical circuit, and the distance between metallized holes does not exceed 5 mm.

 In the inventive electronic unit, the width of the shielding conductors made along the perimeter of the first zone in the outer first and sixth conductive layers is selected at least 2 mm.

 In the inventive electronic block, the distance between the metallized holes of the interlayer connections connecting the shielding conductors made along the perimeter of the first zone in the outer first and sixth conductive layers, between themselves and with the earth planes in the inner second and fifth conductive layers does not exceed 5 mm.

 The essence of the invention, its feasibility and the possibility of industrial application are illustrated by the example of the design of the radio-electronic unit of the navigation receiver-processor, designed to determine the navigation parameters by the signals of the SRNS "GLONASS" and "NAVSTAR". The invention is illustrated by the drawings shown in FIG. 19.

In FIG. 1 shows a sectional view of a multilayer printed circuit board with six conductive layers (the location of the conductors and metallized holes of the interlayer connections is conditional);
in FIG. 2 is an example illustrating the grouping of electro-radio elements mounted in the outer first conductive layer in three consecutive zones (view from the side of the electro-radio elements of the outer first conductive layer, the conductors are not conventionally shown);
in FIG. 3 is an example illustrating the grouping of electro-radio elements mounted in an outer sixth conductive layer in three consecutive zones (view from the side of the outer first conductive layer, the layers are conditionally transparent, the conductors are not conventionally shown);
in FIG. 4 is an example of a print pattern of the outer first conductive layer;
in FIG. 5 is an example of a print pattern of the inner second conductive layer (view from the side of the outer first conductive layer, the layers are conditionally transparent);
in FIG. 6 is an example of a print pattern of the inner third conductive layer (view from the side of the outer first conductive layer, the layers are conditionally transparent);
in FIG. 7 is an example of a print pattern of the inner fourth conductive layer (view from the side of the outer first conductive layer, the layers are conditionally transparent);
in FIG. 8 is an example of a print pattern of the inner fifth conductive layer (view from the side of the outer first conductive layer, the layers are conditionally transparent);
in FIG. 9 is an example of a print pattern of the outer sixth conductive layer (view from the side of the outer first conductive layer, the layers are conditionally transparent).

 The inventive electronic block, FIG. 1 to 9, comprises a multilayer printed circuit board 1 with six conductive layers — an outer first 2 and a sixth 3 conductive layers, an inner second 4, a third 5, a fourth 6 and a fifth 7 conductive layers. The inner (second 4, third 5, fourth 6, fifth 7) conductive layers are separated from each other and from the outer first 2 and sixth 3 conductive layers by insulating layers 8 (Fig. 1).

 In the outer first 2 and sixth 3 conductive layers, the contact pads 9, the conductors 10 are made and the electro-radio elements 11 are mounted (Figs. 1-3). Conductors are made in the inner (second 4, third 5, fourth 6, fifth 7) conductive layers (Figs. 5-8). Interlayer connections of conductors are carried out by means of metallized holes 12 of interlayer connections.

 In FIG. 1 as an example of making metallized holes 12 of the interlayer connections, holes are shown that connect the conductors of the outer first 2 and sixth 3 and the inner second 4 and fifth 7 conductive layers, as well as the outer first 2 and sixth 3 and inner fourth 6 conductive layers.

 The installation of radio electronic elements on the circuit board 1 was made using surface mounting technology, which solves the problem of installing a larger number of them in a smaller area.

 In this example, the implementation of the electronic unit - the receiver-processor unit SRNS - radio elements and conductors are grouped in three consecutive zones 13, 14 and 15 (Fig. 2 - 9).

 The first zone 13 corresponds to the zone of placement of radio-electronic elements performing analogue conversion of SRNS signals, for example, low-integration radio-electronic elements similar to MGA-87563 HEWLETT-PACKARD microcircuits and medium-integration radio-electronic elements similar to MC13142D MOTOROLA and UPC2753GR NEC microcircuits.

 The second zone 14 corresponds to the zone of placement of radio-electronic elements that perform analog-to-digital conversion of signals, for example, radio-electronic elements of medium degree of integration, similar to circuits of the MAX962ESA MAXIM type.

 The third zone 15 corresponds to the zone of placement of radio-electronic elements that perform digital signal conversion, for example, ultra-high integration radio electronic elements similar to TMS320 LC203-40 TEXAS INSTRUMENTS (processor) and ASIC SAMSUNG (digital correlator) microcircuits, highly integrated electrical radio elements similar to V16-KM6 type 15162 SAMSUNG (read-only memory), medium-sized radio electronic elements, similar to microchips like DS1302S DALLAS (timer), small radio-electronic elements No integration similar to MAX604CSA MAXIM chips (stabilizer).

 The conductors in the inner (second 4, third 5, fourth 6, fifth 7) conductive layers are distributed as follows.

 In the inner second conductive layer 4, ground planes 16, 17 and 18 of all three zones 13, 14, 15 are made (FIG. 5).

 In the inner third conductive layer 5, power conductors 19, 20 of the first and second zones 13, 14 and additional conductors 21 of the third zone 15 are made (Fig. 6).

 In the inner fourth conductive layer 6, additional conductors 22, 23 of the first and second zones 13, 14 and a supply plane 24 of the third zone 15 are made (Fig. 7).

 In the inner fifth conductive layer 7, a second earth plane 25 of the first zone 13 and additional conductors 26, 27 of the second and third zones 14, 15 are made (Fig. 8).

 The ground plane 16, 17, 18, made in the second conductive layer 4, are interconnected by direct earth communication conductors 28 (Fig. 5). The width of the ground communication conductors 28 is not less than 1 mm.

 Earth communication conductors 28 (Fig. 5) are located in accordance with the location of the communication signal conductors 29, which carry out electrical connections between the zones in the first 2 and sixth 3 conductive layers (Figs. 4, 9).

 The individual communication signal conductors 29 can be shielded using conductors 30 connected to respective ground planes. Such screening can be carried out, for example, in relation to signal communication conductors carrying signals with the steepest edges or significantly differing in level from the signals of neighboring conductors. In FIG. 4, an example is shown of the shielding of communication signal conductors 29 located in the first conductive layer 2. The conductors 30 for shielding the corresponding communication signal conductor 29 are arranged on both sides thereof and are connected to ground planes to form a closed electrical circuit. Connection with the earth's planes is carried out using the corresponding metallized holes of the interlayer connections made at least at the beginning and at the end of the conductors 30 at a distance from each other not exceeding 5 mm.

 The first zone 13 is surrounded around the perimeter by shielding conductors 31 located opposite each other respectively in the outer first 2 and sixth 3 conductive layers (Fig. 4, 9). The width of the shielding conductors 31 is at least 2 mm. The shielding conductors 31 are connected with each other, as well as with the earth planes 16, 25 in the inner second 4 and fifth 5 conductive layers by means of the metallized holes of the interlayer connections made in them with the formation of a closed electrical circuit. The distance between these metallized holes of the interlayer joints does not exceed 5 mm.

 Shielding conductors 31 have gaps 32 for the passage of the corresponding signal communication conductors 29 (Fig. 4, 9). The sections of the gaps 32 of the shielding conductors 31 in the outer first 2 and sixth 3 conductive layers correspond to solid metallized sections 33 of the earth planes 16 and 25 in the inner second 2 and fifth 7 conductive layers (Fig. 5, 8).

 The indicated design measures provide the necessary protection against spurious interference and induced interference of the electro-radio elements of the first zone 13, which are most sensitive to interference and interference, while the presence of metallized sections 33 of the earth planes 16 and 25, corresponding to the sections of the gaps 32 in the shielding conductors 31, optimizes return circuits for signal circuits that carry out electrical communications between zones. These protective measures against spurious interference and induced interference are effective in conjunction with the proposed location of the ground planes and power conductors in different internal conductive layers, which ensures their necessary shielding.

 To eliminate unwanted short circuits between the metallized holes 12 of the interlayer connections, the earth planes 16-18, 25 and the power plane 24, the windows 34 are deprived of metallization in the corresponding places of these planes (Fig. 1) to place the metallized holes 12 of the interlayer connections.

 A low-frequency connector 35 is used to connect the inventive radio-electronic unit with external devices and a power source, and a high-frequency connector 36, both mounted on the outer first conductive layer 2, is used to connect to the input signal source (Fig. 2).

 To enable the operation of the inventive radio-electronic unit, a power source and other external devices necessary for the unit’s operation — a control panel, an indicator of navigation parameters, etc., are connected to a low-frequency connector 35, and an input signal source, for example, a receiving antenna cable — is connected to a high-frequency connector 36 not shown in the drawings).

 The input signals of the inventive radio electronic unit, which are analog pseudo-noise (broadband) SRNS signals with frequencies in the range from 1200 MHz to 1700 MHz, are fed through the high-frequency connector 36 to the radio electronic elements of the first zone 13, where they undergo the necessary amplification, filtering from noise and frequency conversion with decreasing frequencies up to tens of megahertz. The signals converted in this way in the first zone 13 are then subjected to multichannel analog-to-digital processing in the second zone 14, and then to the correlation processing in a digital processor formed by the electric and radio elements of the third zone 15.

 Thus, in the inventive radio-electronic unit, the signals in the process of processing are sequentially transferred from one zone to another, undergoing a change in frequency from thousands of megahertz at the input of the first zone 13 (zones of the placement of radio electronic elements performing analog signal conversion) to units of hertz at the output of the third zone 15 (zone of the placement of radio electronic elements that perform digital signal conversion).

 Moreover, due to the totality of the proposed design measures, consisting in the proposed grouping of electro-radio elements and conductors by zones, in the proposed arrangement of ground and power planes by zones and by various internal conductive layers, in the proposed screen version of the first zone 13, as well as in the proposed implementation of the connections between the zones by means of signal communication conductors 29 and earth communication conductors 28, in the inventive radio-electronic unit, the elimination of spurious interference and induced interference in a given s conditions substantial difference in the nature and frequency and degree of integration of electronic components.

 So, in the inventive radio-electronic unit due to the proposed design measures, the return circuits of the signal paths connecting various zones to each other are optimized, which minimizes spurious interference and induced interference. In particular, the width of the ground connection conductors 28 (at least 1 mm) is selected from the condition of minimizing losses in the return circuits of the signal paths and reducing their susceptibility to radiation and crosstalk by eliminating non-optimal current paths with additional inductance. The minimized losses in the return circuits of the signal paths are also positively influenced by the proposed design and location of the ground planes 16, 17, 18, 25 and the power plane 24, due to which the formation of the most optimal return circuits corresponding to the signal paths is ensured in the inventive radio-electronic unit the formation of stray current circuits characterized by stray inductances and susceptibility to interference, and the minimum possible resistance n DC and virtually eliminates the voltage drop in the circuit board.

 These design parameters - the width (not less than 2 mm) of the shielding conductors 31, the distance (not more than 5 mm) between the metallized holes of the interlayer connections made in the shielding conductors 31 and the conductors 30, characterize the implementation of the inventive radio electronic unit in the best embodiment.

 Thus, the totality of the considered structural measures allows us to solve the technical problem in the inventive radio electronic unit to eliminate spurious interference and induced interference under given conditions, when heterogeneous electrical radio elements of various degrees of integration are implemented on the multilayer printed circuit board of the unit, which realize the SRNS navigation receiver-processor in which the frequencies of the processed Signals vary from thousands of megahertz at the input to units of hertz at the output.

 The experiments conducted on the manufactured samples of electronic blocks of the claimed design showed that the elimination of spurious interference and induced noise, required from the conditions for ensuring the operability of the blocks, is provided by processing the GLONASS and NAVSTAR SRNS signals in their various combinations and in all their operating ranges frequencies.

 Thus, it can be seen from the above that the claimed radio-electronic unit is technically feasible, industrially feasible, and solves the stated technical problem of eliminating spurious interference and induced noise under the given conditions for the implementation of a small-sized radio-electronic unit that functions as a navigation receiver-processor of the SRNS implemented on one multilayer printed circuit board carrying heterogeneous (analog, analog-to-digital, digital) functional electro-radio elements of different degrees of integration, and the frequency range of the processed and converted signals ranges from thousands of megahertz at the input to units of hertz at the output.

Sources of information
1. On-board devices of satellite radio navigation / I.V. Kudryavtsev, I.N. Mishchenko, A.I. Volynkin and others. Ed. V.S.Shebshaevich. M .: Transport, 1988.

 2. RF patent 2013897, H 05 K 7/00, publ. 05/30/94.

 3. Copyright certificate of the USSR 1826853, N 05 K 5/00, publ. 11/20/96.

 4. RF patent 2047947, H 05 K 1/02, publ. 11/10/95.

 5. Lund P. Precision printed circuit boards. Design and production. M .: Energoatomizdat, 1983.

 6. Mayorov S.A. and other electronic computers. Design Reference. Ed. S.A. Mayorova. M .: Sov. Radio, 1975 (p. 258-261, Fig. 12.2 - prototype).

Claims (5)

 1. An electronic block containing a multilayer printed circuit board in which the interlayer connections of the conductors are carried out by means of metallized holes of the interlayer connections, in which the conductors, contact pads and electrical components are mounted in the outer conductive layers, and the conductors and ground and power planes are made in the inner conductive layers windows around metallized holes of interlayer connections not electrically connected to these planes, characterized in that the elements and conductors are grouped in three consecutive zones, the first of which corresponds to the zone of placement of radio electronic elements performing analogue signal conversion of satellite radio navigation systems, the second to the zone of placement of radio electronic elements performing analog-to-digital signal conversion, and the third to the zone of placement of radio-electronic elements performing digital signal conversion, moreover, the radio-electronic elements are mounted on a multilayer printed circuit board with six wires in layers, where low-frequency and high-frequency connectors are installed on the outer first conductive layer for connecting the radio-electronic unit, respectively, to the power source and input signal source, the ground plane of each of the zones is made in the inner second conductive layer, the third conductors of the first and second zones and additional conductors of the third zone; in the fourth, additional conductors of the first and second zones and the power plane of the third zone are made; in the fifth, the second ground plane the first zone and additional conductors of the second and third zones, while the earth planes made in the inner second conductive layer are interconnected by direct earth communication conductors located in accordance with the location of the communication signal conductors, carrying out electrical communications in the first and sixth conductive layers. between the zones, the first zone is surrounded around the perimeter by shielding conductors made against each other in the outer first and sixth conductive layers, and these screens The conducting conductors are connected with each other, as well as with the ground planes of this zone in the inner second and fifth conductive layers by means of the metallized holes of the interlayer connections made in them with the formation of a closed electrical circuit, these shielding conductors have gaps for the passage of the corresponding signal communication conductors, while the gaps shielding conductors in the outer first and sixth conductive layers correspond to solid metallized sections of the ground planes inward the second and fifth conductive layers.  2. The radio-electronic unit according to claim 1, characterized in that the width of the earth communication conductors that connect the earth planes to each other in the inner second conductive layer is selected at least 1 mm.  3. The radio-electronic unit according to claim 1, characterized in that the printed conductors intended for shielding the corresponding signal communication conductor are located on both sides thereof and are connected to the ground planes through metallized holes of the interlayer connections made at least at the beginning and at the end of each from shielding conductors with the formation of a closed electrical circuit, and the distance between the metallized holes does not exceed 5 mm  4. The radio-electronic unit according to claim 1, characterized in that the width of the shielding conductors made along the perimeter of the first zone in the outer first and sixth conductive layers is selected at least 2 mm.  5. The radio-electronic unit according to claim 1, characterized in that the distance between the metallized holes of the interlayer connections connecting the screening conductors made along the perimeter of the first zone in the outer first and sixth conductive layers to each other and to the ground planes in the inner second and fifth conductive layers is not exceeds 5 mm.

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