CA1195003A - Arrangement for converting the sampling frequencies of n time discrete or digital signals - Google Patents
Arrangement for converting the sampling frequencies of n time discrete or digital signalsInfo
- Publication number
- CA1195003A CA1195003A CA000405701A CA405701A CA1195003A CA 1195003 A CA1195003 A CA 1195003A CA 000405701 A CA000405701 A CA 000405701A CA 405701 A CA405701 A CA 405701A CA 1195003 A CA1195003 A CA 1195003A
- Authority
- CA
- Canada
- Prior art keywords
- arrangement
- devices
- terminals
- sampling frequency
- individual
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04J—MULTIPLEX COMMUNICATION
- H04J3/00—Time-division multiplex systems
- H04J3/16—Time-division multiplex systems in which the time allocation to individual channels within a transmission cycle is variable, e.g. to accommodate varying complexity of signals, to vary number of channels transmitted
- H04J3/1605—Fixed allocated frame structures
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Transmission Systems Not Characterized By The Medium Used For Transmission (AREA)
- Analogue/Digital Conversion (AREA)
Abstract
Abstract of the Disclosure A circuit arrangement for effecting conversions between n different signals each having a different sampling frequency and among which there are K
possible sampling frequency ratios, where
possible sampling frequency ratios, where
Description
27371~8 BACKGROUND OF THE INVENTION
The present inYention relates to an arrangement for the alternating conversion o~ n time dîscrete or digital signals, all furnished at different sampling frequencies.
Such arrangements are used, for example, as interface devices for matching, interpolation or synchronization of time discrete or digital signals at different sampling frequencies.
Individual conversions of one sampling frequency fAl to another fA2 and vice versa are disclosed, for example, in a paper by R.E. Crochiere and L.R. Rabiner, entitled 7'Interpolation and Decimation of Digital Signals -A Tutorial Review", Proceedings of the IEEE, Vol. 69, No. 3, March 1981, pages 300 - 331, and a paper by R. Lagadec, H.O. Kunz, entitled "A New Approach to Digital Sampling Frequency Conversion", AES Audio Engineering Society Pre-print, presented at the 68th Convention March 17 - 20th) 1981, at Hamburg.
Accordi[lg to these disclosures, a substan*ially Eree selection can be made of the sampling frequencies fAl and fA2 by switching parameters. But no multiple conversions are possible. To realize a multiple conve-rsion, an indivi-dual conversion device must be provided Eor each given ratio oE fAl/EA2. In tlle system disclosed in Lagadec et a], interpolation errors cannot be excluded and, morcovcr~ the process requires a very high processing rate.
_J~IM~RY OF TIIE INVE~TION
It is an object of the present invention to provide an arrangemen-t for the alternating conversion of a sampling frequency with which it is possible to convert a sampling frequency simultaneously into a plurality of other samp-ling frequencies and to mix signals having different sampling frequencies.
Another object oE the invention is ~o avoid interpolation errors and the need for very high processing rates.
A further object of ~he invention is ~o reduce the cost of mtmufactur-ing such arrangement.
The above and other objects are achieved, according to the invention~
by the provision of a circuit arrangement for effecting conversions between n different signals each having a differen~ sampling frequency and among which there are K possible sampling frequency ratios, where K = ~ ~n-i~, each represented by a quotient of positive integers lv/mv, where v = 1, 2, 3...K, Iv ~ mv for all values of v, .md for at least one value v, neither lv/mv nor mv/lv is an integer, the arrangemen~ including n-l individual frequency conver-sion devices each having two terminals between which one o-f ~he sampling fre-quency ratios is established, and means connecting the devices into a network having n terminals at each of which a respective signal appears and in which K-(n-l) pairs of terminals are each connected via a respective cascade connection of at least two of the devices.
The invention will now be explained in greater detail ~ith reference to exemplary embodiments illustrated in the drawings.
BRIEP DESCRIPTI~N OF THE DRAWINGS
Figure 1 is a schematic view of a network for linking six sampling Ere-
The present inYention relates to an arrangement for the alternating conversion o~ n time dîscrete or digital signals, all furnished at different sampling frequencies.
Such arrangements are used, for example, as interface devices for matching, interpolation or synchronization of time discrete or digital signals at different sampling frequencies.
Individual conversions of one sampling frequency fAl to another fA2 and vice versa are disclosed, for example, in a paper by R.E. Crochiere and L.R. Rabiner, entitled 7'Interpolation and Decimation of Digital Signals -A Tutorial Review", Proceedings of the IEEE, Vol. 69, No. 3, March 1981, pages 300 - 331, and a paper by R. Lagadec, H.O. Kunz, entitled "A New Approach to Digital Sampling Frequency Conversion", AES Audio Engineering Society Pre-print, presented at the 68th Convention March 17 - 20th) 1981, at Hamburg.
Accordi[lg to these disclosures, a substan*ially Eree selection can be made of the sampling frequencies fAl and fA2 by switching parameters. But no multiple conversions are possible. To realize a multiple conve-rsion, an indivi-dual conversion device must be provided Eor each given ratio oE fAl/EA2. In tlle system disclosed in Lagadec et a], interpolation errors cannot be excluded and, morcovcr~ the process requires a very high processing rate.
_J~IM~RY OF TIIE INVE~TION
It is an object of the present invention to provide an arrangemen-t for the alternating conversion of a sampling frequency with which it is possible to convert a sampling frequency simultaneously into a plurality of other samp-ling frequencies and to mix signals having different sampling frequencies.
Another object oE the invention is ~o avoid interpolation errors and the need for very high processing rates.
A further object of ~he invention is ~o reduce the cost of mtmufactur-ing such arrangement.
The above and other objects are achieved, according to the invention~
by the provision of a circuit arrangement for effecting conversions between n different signals each having a differen~ sampling frequency and among which there are K possible sampling frequency ratios, where K = ~ ~n-i~, each represented by a quotient of positive integers lv/mv, where v = 1, 2, 3...K, Iv ~ mv for all values of v, .md for at least one value v, neither lv/mv nor mv/lv is an integer, the arrangemen~ including n-l individual frequency conver-sion devices each having two terminals between which one o-f ~he sampling fre-quency ratios is established, and means connecting the devices into a network having n terminals at each of which a respective signal appears and in which K-(n-l) pairs of terminals are each connected via a respective cascade connection of at least two of the devices.
The invention will now be explained in greater detail ~ith reference to exemplary embodiments illustrated in the drawings.
BRIEP DESCRIPTI~N OF THE DRAWINGS
Figure 1 is a schematic view of a network for linking six sampling Ere-
2() ~luollcles.
~ igure 2 is a block circuit diagram of one embodiment oE a circuittlccordillg to tl~e invention Eor linking those frequencies.
Figure 3 is a schematic view of the network formed by the circuit of Figure 2.
Figure 4 is a view similar to that of Figure 2 oE a Eurther embodimen~
of a circuit according to the invention which is particularly economical.
Figure 5 is a schematic view of the network formed by ~he circuit of Figure 4.
DESCRIPTION OF THE PREFERRED EMODIMENTS
Figure 1 shows a network of links for n = 6 sampliny frequencies as occur in a digital sound system in a recording studio.
The most frequently encountered sampling frequencies are assumed to be, for example A = 50.4 k~z, B = 32 kHz, C = 44.1 kl-lz, D = 47.25 k~z, E = 48 k~lz, F = 50 kHz, The number, K, of all possible conversion ratios here is as follows:
n 6 K = ~ ~n~ (6-i) = 15 1=1 i=l Individually, these converstion ratios, each represented by the quotient of positive integers lv/mv, are:
A:B = 63: 40 B:C = 320:441 C:E = 147:160 A:C = 8: 7 B:D = 128:189 C:F = 441:500 A:D = 16: 15 B:E = 2: 3 D:E = 63: 64 A:E = 21: 20 B:F = 16: 25 D:F = 189:200 A:F =126:125 C:D = 14: 15 E:F = 24: 25 Ilowever, according to the invention, individual clevices ed be provided to produce only five of these 15 conversion ratios.
'l`he remaining 10 ratios can be achieved by cascade connection of the indlvidual devices.
Thus, Figure 2 shows one preferred emodiment of such a network. It mus-t here be realized that the manufacturing costs for the individual devices will be greater, the larger are the integer factors lv and mv; because the greater lv and mv, the more filter coefficients must be provided. Thus the factors 1 and m should preferably be relatively rime.
Figure 3 shows the network provided by the circuit of Figure 2. The solid li.nes represent the conversion effected by individual devices. The broken -3a-5~3 lines represent the conversions effected by a cascade connection of two, three or four of the individual devices.
Figure 4 shows a second embodiment of a network which is more favour-able with respect to costs.
Figure 4 shall serve to explain how the device according to the inven-tion for changing ~he sampling frequency can be used to mix signals which are furnished at diEferent sampling frequencies. If, for example, in Figure 4 *he block A/C is operated in -the direction C ~ A and block A/D in the direction ~ A, the signal originally sampled a-t C is superposed on, or mixed with, the other signal originally sampled at D at the summing point Sl associated with the sampling frequency A. The realization of this possibility may employ additional time discrete or digital regulators for amplitude evaluations as described by . Sakamoto et al, "A professional digital audio mixer", AES Audio Engineering Society Preprint, presented at the 67th Convention 0ct. 31 - Nov. 3, 1980 at New York. This paper treats the problem of mixing audio signals, where the amplitude oE each signal is individually controllable. Proposals for preferrable om~oclimcnts of mixing devices ~accumulator) and digital potentiometers (multi-plier) are given in this paper in Figures 3 - 5.
As described earlier herein, one signal can simultaneously be recorded 2() to a plurality of diEEerent sampling frequencies, as can be seen directly in l:iguro ~, for example. In such a case in particular, it is appropriate to de-rive thc clock pu]se for the entire arrangement from one oE the incoming s;gnals.
I:or this purpose, an input signal will be selected whose sampling frequency it-self is not syncllronizable. A sampling frequency is~ -for instance, not synchron-i~able, if it is fed into the system under consideration from another system whose parameters cannot be controlled from this location.
Figure 5 shows the network associated with Figure ~.
A favourable operative embodiment of each of the individual frequency conversion devices is described in detail in the paper by Crochiere et al (sec-tion III D) cited above. Further details concerning hardware mechanization can be found in L. Schirm IV "Multiplier Accumulator application notes", TRW LSI
products, El Segundo, CA 90245, Jan. 1980, pp 6 - 8.
It will be understood that the above description of the present in-vention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equival-ents of the appended claims.
~ igure 2 is a block circuit diagram of one embodiment oE a circuittlccordillg to tl~e invention Eor linking those frequencies.
Figure 3 is a schematic view of the network formed by the circuit of Figure 2.
Figure 4 is a view similar to that of Figure 2 oE a Eurther embodimen~
of a circuit according to the invention which is particularly economical.
Figure 5 is a schematic view of the network formed by ~he circuit of Figure 4.
DESCRIPTION OF THE PREFERRED EMODIMENTS
Figure 1 shows a network of links for n = 6 sampliny frequencies as occur in a digital sound system in a recording studio.
The most frequently encountered sampling frequencies are assumed to be, for example A = 50.4 k~z, B = 32 kHz, C = 44.1 kl-lz, D = 47.25 k~z, E = 48 k~lz, F = 50 kHz, The number, K, of all possible conversion ratios here is as follows:
n 6 K = ~ ~n~ (6-i) = 15 1=1 i=l Individually, these converstion ratios, each represented by the quotient of positive integers lv/mv, are:
A:B = 63: 40 B:C = 320:441 C:E = 147:160 A:C = 8: 7 B:D = 128:189 C:F = 441:500 A:D = 16: 15 B:E = 2: 3 D:E = 63: 64 A:E = 21: 20 B:F = 16: 25 D:F = 189:200 A:F =126:125 C:D = 14: 15 E:F = 24: 25 Ilowever, according to the invention, individual clevices ed be provided to produce only five of these 15 conversion ratios.
'l`he remaining 10 ratios can be achieved by cascade connection of the indlvidual devices.
Thus, Figure 2 shows one preferred emodiment of such a network. It mus-t here be realized that the manufacturing costs for the individual devices will be greater, the larger are the integer factors lv and mv; because the greater lv and mv, the more filter coefficients must be provided. Thus the factors 1 and m should preferably be relatively rime.
Figure 3 shows the network provided by the circuit of Figure 2. The solid li.nes represent the conversion effected by individual devices. The broken -3a-5~3 lines represent the conversions effected by a cascade connection of two, three or four of the individual devices.
Figure 4 shows a second embodiment of a network which is more favour-able with respect to costs.
Figure 4 shall serve to explain how the device according to the inven-tion for changing ~he sampling frequency can be used to mix signals which are furnished at diEferent sampling frequencies. If, for example, in Figure 4 *he block A/C is operated in -the direction C ~ A and block A/D in the direction ~ A, the signal originally sampled a-t C is superposed on, or mixed with, the other signal originally sampled at D at the summing point Sl associated with the sampling frequency A. The realization of this possibility may employ additional time discrete or digital regulators for amplitude evaluations as described by . Sakamoto et al, "A professional digital audio mixer", AES Audio Engineering Society Preprint, presented at the 67th Convention 0ct. 31 - Nov. 3, 1980 at New York. This paper treats the problem of mixing audio signals, where the amplitude oE each signal is individually controllable. Proposals for preferrable om~oclimcnts of mixing devices ~accumulator) and digital potentiometers (multi-plier) are given in this paper in Figures 3 - 5.
As described earlier herein, one signal can simultaneously be recorded 2() to a plurality of diEEerent sampling frequencies, as can be seen directly in l:iguro ~, for example. In such a case in particular, it is appropriate to de-rive thc clock pu]se for the entire arrangement from one oE the incoming s;gnals.
I:or this purpose, an input signal will be selected whose sampling frequency it-self is not syncllronizable. A sampling frequency is~ -for instance, not synchron-i~able, if it is fed into the system under consideration from another system whose parameters cannot be controlled from this location.
Figure 5 shows the network associated with Figure ~.
A favourable operative embodiment of each of the individual frequency conversion devices is described in detail in the paper by Crochiere et al (sec-tion III D) cited above. Further details concerning hardware mechanization can be found in L. Schirm IV "Multiplier Accumulator application notes", TRW LSI
products, El Segundo, CA 90245, Jan. 1980, pp 6 - 8.
It will be understood that the above description of the present in-vention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equival-ents of the appended claims.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A circuit arrangement for effecting conversions between n different signals each having a different sampling frequency and among which there are K
possible sampling frequency ratios, where , each represented by a quotient of positive integers 1v/mv, where v=1, 2, 3...K, 1v ? mv for all values of v, and for at least one value v, neither 1v/mv nor mv/1v is an inte-ger, said arrangement comprising n-1 individual frequency conversion devices each having two terminals between which one of the sampling frequency ratios is established, and means connecting said devices into a network having n terminals at each of which a respective signal appears and in which K-(n-1) pairs of terminals are each connected via a respective cascade connection of at least two of said devices.
possible sampling frequency ratios, where , each represented by a quotient of positive integers 1v/mv, where v=1, 2, 3...K, 1v ? mv for all values of v, and for at least one value v, neither 1v/mv nor mv/1v is an inte-ger, said arrangement comprising n-1 individual frequency conversion devices each having two terminals between which one of the sampling frequency ratios is established, and means connecting said devices into a network having n terminals at each of which a respective signal appears and in which K-(n-1) pairs of terminals are each connected via a respective cascade connection of at least two of said devices.
2. An arrangement as defined in claim 1 wherein said devices are cons-tructed such that the ratios between said terminals of said devices are those corresponding to the smallest possible values for 1v and mv.
3. Arrangement as defined in claim 1 further comprising a signal mix-ing device selectively provided at each summing point Sj between two frequency conversion devices.
4. Arrangement as defined in claim 3 wherein all said individual devices and all said mixing devices are constituted by digital circuit means.
5. Arrangement as defined in claim 3 wherein all said individual devices and said mixing devices process signals supplied thereto in a time discrete manner.
6. Arrangement as defined in claim 1 or 2 wherein said individual devices derive all sampling frequencies from the sampling frequency of one signal.
7. Arrangement as defined in claim 1 or 2 wherein all said individual devices are constituted by digital circuit means.
8. Arrangement as defined in claim 1 or 2 wherein individual devices process signals supplied thereto in a time discrete manner.
9. Arrangement as defined in claim 1 wherein the signals are digital signals.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3124518.8 | 1981-06-23 | ||
| DE19813124518 DE3124518A1 (en) | 1981-06-23 | 1981-06-23 | ARRANGEMENT FOR INTERCHANGEABLE IMPLEMENTATION OF THE Sampling FREQUENCY OF N TIME DISCRETE OR DIGITAL SIGNALS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1195003A true CA1195003A (en) | 1985-10-08 |
Family
ID=6135137
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000405701A Expired CA1195003A (en) | 1981-06-23 | 1982-06-22 | Arrangement for converting the sampling frequencies of n time discrete or digital signals |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0068150B1 (en) |
| CA (1) | CA1195003A (en) |
| DE (2) | DE3124518A1 (en) |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3745471A (en) * | 1971-12-28 | 1973-07-10 | Gen Electric | Multiple output frequency reference wave generator |
| BE794152A (en) * | 1972-01-18 | 1973-07-17 | Bayer Ag | MONOAZOIC DYES |
| FR2194076B1 (en) * | 1972-07-27 | 1976-10-29 | Neo Tec Etude Applic Tech | |
| DE2509451A1 (en) * | 1974-03-15 | 1975-09-25 | Philips Nv | FREQUENCY CONVERTER FOR GENERATING A TONE FROM ANOTHER TONE |
-
1981
- 1981-06-23 DE DE19813124518 patent/DE3124518A1/en not_active Withdrawn
-
1982
- 1982-05-27 EP EP82104611A patent/EP0068150B1/en not_active Expired
- 1982-05-27 DE DE8282104611T patent/DE3260144D1/en not_active Expired
- 1982-06-22 CA CA000405701A patent/CA1195003A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| EP0068150B1 (en) | 1984-05-09 |
| EP0068150A1 (en) | 1983-01-05 |
| DE3260144D1 (en) | 1984-06-14 |
| DE3124518A1 (en) | 1983-05-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |