CN2030776U - Digital voice gaussian noise generator - Google Patents
Digital voice gaussian noise generator Download PDFInfo
- Publication number
- CN2030776U CN2030776U CN 88200391 CN88200391U CN2030776U CN 2030776 U CN2030776 U CN 2030776U CN 88200391 CN88200391 CN 88200391 CN 88200391 U CN88200391 U CN 88200391U CN 2030776 U CN2030776 U CN 2030776U
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- digital
- eprom
- white noise
- noise generator
- gaussian
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- Testing Electric Properties And Detecting Electric Faults (AREA)
Abstract
The utility model discloses a hardware implementation digital Gaussian white noise generator which is used for the frequency band of speech path measuring. The utility model has the advantages of simple circuit realization, stable performance, low cost and small size. The implementation procedure is using the output of m sequence as the EPROM address in parallel to visit the digital quantities which are existing in the EPROM. The digital quantities are treated as the input of D/A and are programmed by a digital-analogue converter D/A, then the digital-analogue converter D/A outputs the digital quantities, and finally the quantities are outputted by magnification, low pass and attenuation. The number of digital quantities existing in the EPROM obeys the Gaussian distribution.
Description
This equipment is a kind of hard-wired Gaussian white noise generator, is applicable to the measurement of voice grade frequency band.The output level of this Gaussian white noise generator is-45dB-0dB that output impedance is 600 Ω.
Present Gaussian white noise generator is analog, it by analog signal that noise diode produced as noise source.Because the signal level that noise diode produced is low especially, has high-gain with regard to the amplifying circuit that requires the back like this, broadband and linear phase.The Gaussian white noise generator circuit is complicated to be increased with cost thereby cause.And the characteristic of noise diode is owing to the variation of surrounding environment, and too of a specified duration or other reason of time spent can cause the noise diode characteristic to degenerate, and may cause the output of signal not to be white Gaussian noise when serious.
The purpose of this invention is to provide a kind of Gaussian white noise generator that has than present Gaussian white noise generator stable performance, cheap, advantage such as volume is little, power consumption is little.
This equipment is digital, its implementation is as follows, utilize the character of the correlation function of pseudo-randomness that the m sequence had and the approximate white noise of correlation function thereof, first of m sequence is listed as the output of the tenth row, but parallel address as erasable read only memory EPROM, along with m sequence lengthening, its pseudo-randomness is stronger.Here the effect of EPROM is to be used for storing numerical value, and the number Gaussian distributed of its numerical value, 8 with EPROM export parallel inputs of receiving the D/A digital to analog converter then.The output of D/A digital to analog converter just can obtain required white Gaussian noise at last through amplifier, low pass filter, emitter follower, attenuator.
Adjoint is that the present invention is described in further detail for embodiment.
The block diagram of Fig. 1 Gaussian white noise generator.
Fig. 2 Gaussian white noise generator
Fig. 3 stepping adjustable attenuator circuit.
In Fig. 1, (1) is the m sequencer on 28 rank, and the primitive polynomial of m sequencer is f(x)=1+x
3+ x
28, the clock of m sequencer is 250KHz.(2) but be the erasable read only memory EPROM of 1K byte of memory.(3) be the D/A digital to analog converter of 8 inputs.(4) comprise amplifier, low pass second-order active filter device, emitter follower, attenuator for output.
In Fig. 2, (13), (14), (15), (16) are respectively the chip of 8 d type flip flops, and (13), (14), (15) have been used 8 d type flip flops respectively, and (16) have only used 4 d type flip flops, and the model of (13)～(16) is 74LS273.(13), (14), (15), (16) chip have been formed the m sequence on 28 rank.(5), the model of (7), (9), (10) is 74S260, they are NOR gate.(6), (8) be NAND gate, model is TO65BE.(11) be or the door, model is 74LS32.(5) formed the zero testing circuit of m sequence to (11).NAND gate (17) is formed multivibrator with peripheral circuit electric capacity (29), resistance (30), and the cycle of oscillator is by electric capacity (29), resistance (30) decision.The effect of multivibrator is the clock pulse that is used for d type flip flop.The output frequency of multivibrator is 250KHz.(17) model TO65BE.(30) select general metallic resistance for use, (29) select general ceramic condenser for use.First of m sequence is listed as the output of the tenth row, but parallel input as erasable read only memory EPROM (2), the model of EPROM is 74LS2716, save as the 2K byte in 2716, used the 1K byte of low side here, in the internal memory of this 1K byte, the numerical value of depositing is OO～FF, the number Gaussian distributed of institute's poke value.Wherein at 80(hexadecimal) near the number of the numerical value deposited many, and at two, promptly the number of institute's poke value is fewer near OO, the FF.The parallel input of receiving D/A digital to analog converter (3) of 8 outputs with EPROM.D/A digital to analog converter (3) model is DACO832.Then again with the output of the D/A digital to analog converter input as amplifier (19), signal is through amplifier, second order universal active filter (18,21,22,23,24), emitter follower, adjustable attenuator (19,25,26), stepping adjustable attenuator (20) obtain exporting white noise at last continuously like this.Under the situation of decay minimum, make last output power levels reach 0dB.Transport and placing device (18) is formed the second order active low-pass filter with resistance (21), (23), electric capacity (22), (24), and its cut-off frequency is 20KHz, and the model of (18) is LF374.Transport and placing device (19) is formed amplifier, emitter follower and continuous adjustable attenuator with resistance (25), (26).(21), (23), (25) are metalfilmresistor, (26) be the adjustable metal film resistance, (22), (24) are electric capacity of the dacron, and resistance (27), (28) are the inverted L shape resistor network, be used for finishing impedance matching, (27), (28) are metalfilmresistor.Stepping adjustable attenuator (20) is to be finished by symmetric double T resistor network.
Stepping adjustable attenuator (Fig. 3) is (20) of Fig. 2, and resistance (31) is metalfilmresistor to (52), and (53), (54) are the contact of switch.This network is a pure resistance network, and it is a symmetric double T resistor network, and its damping capacity can reach 30dB.It can be finished under the situation that changes attenuation multiple, does not change its output impedance, guarantees that output impedance is 600 Ω.(12) be storbing gate, model 74LS86P.
This device power supply (DPS) is selected multiple power source for use.
By above explanation as seen, this is a kind of New Digital voice grade Gaussian white noise generator, and it can eliminate the various shortcomings of in the past simulating Gaussian white noise generator, and has simple in structurely, and volume is little, and power consumption is little, inexpensive and the advantage of being convenient to produce.
Claims (3)
1, a kind of Gaussian white noise generator that is used for voice grade frequency band snr measurement, have noise source, amplifier, attenuator, it is characterized in that but noise source is by 28 rank m sequencers and erasable read only memory EPROM[2] constitute, digital noise changes device D/A[3 through digital-to-analogue] be output as general simulating the white noise.
2, Gaussian white noise generator according to claim 1 is characterized in that the m sequencer on 28 rank, and the employing primitive polynomial is f(x)=1+X
3+ X
28, clock is 250KHz.
3,, it is characterized in that first of m sequence is listed as the output of the tenth row, parallel address, the number Gaussian distributed of EPROM institute poke value as EPROM (2) according to claim 1,2 described Gaussian white noise generators.The parallel input of 8 outputs of EPROM as D/A digital to analog converter (3).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88200391 CN2030776U (en) | 1988-01-21 | 1988-01-21 | Digital voice gaussian noise generator |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88200391 CN2030776U (en) | 1988-01-21 | 1988-01-21 | Digital voice gaussian noise generator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN2030776U true CN2030776U (en) | 1989-01-11 |
Family
ID=4835833
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88200391 Withdrawn CN2030776U (en) | 1988-01-21 | 1988-01-21 | Digital voice gaussian noise generator |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN2030776U (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1051662C (en) * | 1994-03-18 | 2000-04-19 | 山东省信玉电子行 | automatic radio interference and communication device |
| CN100533551C (en) * | 2001-10-26 | 2009-08-26 | 摩托罗拉公司(特拉华) | Generating percussive sounds in embedded devices |
| CN102201788A (en) * | 2011-05-11 | 2011-09-28 | 清华大学 | Digital noise generation method |
-
1988
- 1988-01-21 CN CN 88200391 patent/CN2030776U/en not_active Withdrawn
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1051662C (en) * | 1994-03-18 | 2000-04-19 | 山东省信玉电子行 | automatic radio interference and communication device |
| CN100533551C (en) * | 2001-10-26 | 2009-08-26 | 摩托罗拉公司(特拉华) | Generating percussive sounds in embedded devices |
| CN102201788A (en) * | 2011-05-11 | 2011-09-28 | 清华大学 | Digital noise generation method |
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|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |