An audio alarm synthesis method suitable for medical electrical alarm system

Abstract

The present invention discloses an audio alarm synthesis method suitable for a medical electrical alarm system, comprising the steps of (A): constructing a timing signal generator; (B): constructing an envelope generator; (C): constructing a note sequencer; (D): constructing a note generator; and (E): detecting an alarm signal and outputting a DAC. The audio alarm synthesis method suitable for a medical electrical alarm system of the present invention generates an alarm in the form of an algorithm, which is a very effective method in terms of memory utilization, and allows considerable flexibility, and can customize the notes while meeting the YY 0709-2009 technical specifications, without requiring a large amount of memory space to store alarm files in the form of recordings, and without requiring a large amount of program space to control playback; the present invention provides a note sequencer of three alarm types, namely, high, medium, and low, to distinguish different alarms, generate different alarm tones, and different alarm sounds, so as to make it easier to master the alarm.

Description

Technical Field

[0001] The invention relates to an audio alarm synthesis method suitable for a medical electrical alarm system. Background Art

[0002] YY 0709-2009 specifies the requirements for alarm systems in medical electrical equipment and medical electrical systems, specifies specific melody applications and specific physiological functions, specifies the alarm status priority, pulse group characteristics of auditory alarm signals, the number of pulses in the pulse group, pulse interval, pulse group interval, pulse amplitude difference, pulse frequency, number of harmonic components, pulse effective duration, rise time, fall time, etc.

[0003] Traditional medical device alarm implementation schemes all play back alarms in the form of recorded audio stored in memory, but the disadvantage is that it requires a large amount of memory space to store files and program space to control playback. Summary of the invention

[0004] The purpose of the present invention is to provide an audio alarm synthesis method suitable for a medical electrical alarm system, so as to solve the problem that the traditional medical device alarm implementation scheme proposed in the above background technology is to play back the alarm in the form of a recording stored in the memory, which requires a large amount of memory space to store files, and program space to control the playback.

[0005] To achieve the above object, the present invention provides the following technical solution: an audio alarm synthesis method suitable for a medical electrical alarm system, comprising the following steps:

[0006] Step (A): construct a timing signal generator;

[0007] Step (A1), initializing the timing signal generator to provide a timing reference;

[0008] Step (A2), set an interrupt to be generated every 40μs, and set an alarm scan every 1ms;

[0009] Step (B): constructing an envelope generator;

[0010] Step (B1), setting the amplitude of the note pulse;

[0011] Step (B2), setting the rising time and falling time of the note pulse according to the amplitude;

[0012] Step (B3), setting the envelope variable so that when the note is turned on, the envelope variable will increase at a set rate every millisecond until it reaches a set maximum level; when the note is turned off, the tone continues, but the envelope variable begins to decrease at its set rate until it reaches "0";

[0013] Step (C): construct a note sequencer;

[0014] Step (C1), using alarm variables to set the note sequencer for three alarm types: high, medium, and low;

[0015] Step (C2), setting the frequency, number and order of basic notes according to the alarm type and priority, wherein the high-level alarm is {C, A, F, A, F}, the medium-level alarm is {C, A, F, 0, 0}, and the low-level alarm is {E, C, 0, 0, 0}, wherein C is 4 or 5, A is 3, 4 or 5, F is 3, 4 or 5, and E is 3, 4 or 5;

[0016] Step (C3), setting different pulse group numbers, pulse intervals, and pulse durations according to the alarm type;

[0017] Step (D): construct a note generator;

[0018] Step (D1), defining structure labels, constant frequency matrix and algorithm structure matrix;

[0019] Step (D2), generating a single fundamental note and a sine wave of at least four harmonics, and then using a Goertzel algorithm to generate a multiple sine wave tone of the fundamental note and the above harmonics;

[0020] Step (E): Detect alarm signal and DAC output, wherein DAC is a digital-to-analog converter.

[0021] Preferably, in step (D2), the Goertzel algorithm is used to generate multiple sinusoidal tones of basic notes and four harmonics. The specific steps are as follows:

[0022] Step (D21), calculating the sine value of the angle from two previous incremental values ​​in the sine series, wherein x and y are coefficients of the IIR filter, a is the starting angle, b is the incremental angle, and n is the number of detection segment sampling values;

[0023] sin(a+n×b)=x×sin(a+(n-2)×b)+y×sin(a+(n-1)×b);

[0024] Step (D22), substitute the trigonometric identities and rearrange:

[0025] sin(a+n×b)=[x×cos(2×b)+y×cos(b)]×sin(a+n×b)-[x×sin(2×b)+y×sin(b)]×cos(a+n×b);

[0026] Step (D23), ensure that all n are true, solve the coefficient x=-1 of the recursive IIR filter,

[0027] y=2×cos(b), it can be concluded that the calculation at each step angle increment only requires the y[-1] value to be moved into the y[-2] variable, and the calculated y[n] value to be moved into the y[-1] variable to prepare for the calculation at the next step angle.

[0028] Preferably, in step (C2),

[0029] For high priority alarms, the sequence is defined as a 5-note sequence that repeats once for a total of 10 notes;

[0030] For medium priority alarms, the sequence is defined as a 3-note sequence, but without repetition;

[0031] For low priority alarms, the sequence is defined as a 2-note sequence, but without repetition.

[0032] Preferably, the rhythm of the high-priority alarm is faster than the rhythm of the medium-priority alarm.

[0033] Preferably, the step (E) specifically comprises the following steps:

[0034] Step (E1), turn on the clock and set it as analog input;

[0035] Step (E2), enabling the DAC clock;

[0036] Step (E3), setting the DAC working mode;

[0037] Step (E4), DAC output at 25ksps output rate.

[0038] Preferably, in the step (C2): the frequency, number and order of basic notes are set according to the alarm type and priority, wherein the high-level alarm is {C4, A4, F4, A4, F4} and the intermediate alarm is {C4, A4, F4, 0, 0}.

[0039] Preferably, in the step (D2): a single fundamental note and four harmonic sine waves are generated, and then a Goertzel algorithm is used to generate a multiple sine wave tones of the fundamental note and four harmonics.

[0040] Compared with the prior art, the advantages and benefits of the present invention are:

[0041] The algorithmic generation of alarms of the present invention is a very efficient method in terms of memory utilization and allows considerable flexibility in customizing the notes while meeting the YY 0709-2009 technical specifications, without requiring a large amount of memory space to store the alarm files in the form of recordings, nor a large amount of program space to control playback;

[0042] The present invention provides a note sequencer for three alarm types, high, medium and low, to distinguish different alarms, produce different alarm tones, different alarm sounds, and the sequence of three notes of a given alarm type is the same as the first three notes of the same high priority sequence, so that the alarm can be grasped more easily;

[0043] The present invention sets different numbers of pulse groups, pulse intervals, and pulse durations according to the alarm type to distinguish different alarms, and passes the correct notes at the correct beat to meet the instantaneous characteristics of the alarm with a given priority, and different numbers of notes and beat differences can easily distinguish the priority of the alarm. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 It is a schematic diagram of the process of the present invention;

[0045] Figure 2 It is the time characteristic diagram of the alarm signal of the present invention. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] See also Figure 1-2 The present invention provides a technical solution: an audio alarm synthesis method suitable for a medical electrical alarm system, comprising the following steps:

[0048] Step (A): construct a timing signal generator;

[0049] Step (A1), initializing the timing signal generator to provide a timing reference;

[0050] Step (A2), setting an interrupt to be generated every 40 μs, setting an alarm scan every 1 ms; providing a sampling rate of 25 kHz, setting an alarm scan every 1 ms, confirming what kind of alarm information is received by the external interrupt by means of pulse counting; providing a DAC output rate of 25 ksps; the DAC involved in the present invention is a digital-to-analog converter;

[0051] Step (B): constructing an envelope generator;

[0052] Step (B1), setting the amplitude of the note pulse to ensure that the alarm sound can reach the standard sound pressure level;

[0053] Step (B2), according to the amplitude, set the rise time and fall time of the note pulse (different priorities have different rise and fall times), and calculate the rate at which the envelope variable rises or falls;

[0054] Step (B3), setting the envelope variable so that when the note is turned on, the envelope variable will increase at a set rate every millisecond until it reaches the set maximum level; when the note is turned off, the tone continues, but the envelope variable begins to decrease at its set rate until it reaches "0", ensuring that the alarm sound reaches the corresponding amplitude within the specified time in accordance with standard requirements;

[0055] Step (C): construct a note sequencer;

[0056] Step (C1), using alarm variables to set the note sequencer of three alarm types: high, medium and low; to distinguish different alarms, generate different alarm tones, different alarm sounds, and the three-note sequence of a given alarm type is the same as the first three notes of the same high priority sequence, so that the alarm is easier to grasp;

[0057] Step (C2), setting the frequency, number and order of basic notes according to the alarm type and priority, wherein the high-level alarm is {C, A, F, A, F}, the medium-level alarm is {C, A, F, 0, 0}, and the low-level alarm is {E, C, 0, 0, 0}, wherein C is 4 or 5, A is 3, 4 or 5, F is 3, 4 or 5, and E is 3, 4 or 5;

[0058] Step (C3), setting different numbers of pulse groups, pulse intervals, and pulse durations according to the alarm type; to distinguish different alarms, passing the correct notes at the correct beat to meet the instantaneous characteristics of the alarm with a given priority, and different numbers of notes and beat differences can easily distinguish the priority of the alarm;

[0059] Step (D): construct a note generator;

[0060] Step (D1), defining the structure label, the constant frequency matrix and the algorithm structure matrix; the one-to-one correspondence between the matrices makes it easy to use similar indices of the two matrices when initializing each frequency;

[0061] Step (D2), generating a single fundamental note and a sine wave of at least four harmonics, and then using the Goertzel algorithm to generate a multiple sine wave tone of the fundamental note and the above harmonics; in order to easily comply with the standard, the multiple sine wave tones are formed;

[0062] Step (E): Detect alarm signal and DAC output, wherein DAC is a digital-to-analog converter.

[0063] Furthermore, in step (D2), the Goertzel algorithm is used to generate multiple sine wave tones of the basic note and four harmonics. The specific steps are as follows:

[0064] Step (D21), calculating the sine value of the angle from two previous incremental values ​​in the sine series, wherein x and y are coefficients of the IIR filter, a is the starting angle, b is the incremental angle, and n is the number of detection segment sampling values; as shown in Tables 1 and 2 below;

[0065] sin(a+n×b)=x×sin(a+(n-2)×b)+y×sin(a+(n-1)×b);

[0066] Step (D22), substitute the trigonometric identities and rearrange:

[0067] sin(a+n×b)=[x×cos(2×b)+y×cos(b)]×sin(a+n×b)-[x×sin(2×b)+y×sin(b)]×cos(a+n×b);

[0068] Step (D23), ensure that all n are true, solve the coefficient x=-1 of the recursive IIR filter,

[0069] y = 2 × cos(b), it is concluded that the calculation at each step angle increment only requires the y[-1] value to be moved into the y[-2] variable, and the calculated y[n] value to be moved into the y[-1] variable to prepare for the calculation at the next step angle;

[0070]

[0071] Table 1

[0072]

[0073] Table 2

[0074] The algorithmic generation of alarms of the present invention is a very efficient method in terms of memory utilization and allows considerable flexibility in customizing the notes while meeting the YY 0709-2009 technical specifications, without requiring a large amount of memory space to store the alarm files in the form of recordings, nor a large amount of program space to control playback;

[0075] Further, in step (C2),

[0076] For high priority alarms, the sequence is defined as a 5-note sequence that repeats once for a total of 10 notes;

[0077] For medium priority alarms, the sequence is defined as a 3-note sequence, but without repetition;

[0078] For low priority alarms, the sequence is defined as a 2-note sequence, but without repetition.

[0079] Furthermore, the rhythm of the high-priority alarm is faster than the rhythm of the medium-priority alarm.

[0080] Further, step (E) specifically comprises the following steps:

[0081] Step (E1), turn on the clock and set it as analog input;

[0082] Step (E2), enabling the DAC clock;

[0083] Step (E3), setting the DAC working mode;

[0084] Step (E4), DAC output at 25ksps output rate.

[0085] Further, in step (C2): the frequency, number and order of basic notes are set according to the alarm type and priority, wherein the high-level alarm is {C4, A4, F4, A4, F4} and the medium-level alarm is {C4, A4, F4, 0, 0}.

[0086] Furthermore, in step (D2): a separate fundamental note and four harmonic sine waves are generated, and then a Goertzel algorithm is used to generate a multiple sine wave tones of the fundamental note and four harmonics.

[0087] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is limited by the appended claims and their equivalents.

Claims

1. A method for synthesizing an audio alarm suitable for a medical electrical alarm system, characterized in that: The following steps are involved: Step (A): construct a timing signal generator; Step (A1), initializing the timing signal generator to provide a timing reference; Step (A2), set an interrupt to be generated every 40μs, and set an alarm scan every 1ms; Step (B): constructing an envelope generator; Step (B1), setting the amplitude of the note pulse; Step (B2), setting the rising time and falling time of the note pulse according to the amplitude; Step (B3), setting the envelope variable so that when the note is turned on, the envelope variable will increase at a set rate every millisecond until it reaches a set maximum level; when the note is turned off, the tone continues, but the envelope variable begins to decrease at its set rate until it reaches "0"; Step (C): construct a note sequencer; Step (C1), using alarm variables to set the note sequencer for three alarm types: high, medium, and low; Step (C2), setting the frequency, number and order of basic notes according to the alarm type and priority, wherein the high-level alarm is {C, A, F, A, F}, the medium-level alarm is {C, A, F, 0, 0}, and the low-level alarm is {E, C, 0, 0, 0}, wherein C is 4 or 5, A is 3, 4 or 5, F is 3, 4 or 5, and E is 3, 4 or 5; Step (C3), set different pulse group numbers and pulse intervals according to the alarm type. Pulse duration; Step (D): construct a note generator; Step (D1), defining structure labels, constant frequency matrix and algorithm structure matrix; Step (D2), generating a sine wave of a single fundamental note and at least 4 harmonics, Then use the Goertzel algorithm to generate multiple sine wave tones of the fundamental note and the above harmonics; Step (E): Detect alarm signal and DAC output, wherein DAC is a digital-to-analog converter.

2. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 1, characterized in that: In the step (D2), the Goertzel algorithm is used to generate multiple sine wave tones of the basic note and four harmonics. The specific steps are as follows: Step (D21), calculating the sine value of the angle from two previous incremental values ​​in the sine series, wherein x and y are coefficients of the IIR filter, a is the starting angle, b is the incremental angle, and n is the number of detection segment sampling values; sin(a+n×b)=x×sin(a+(n-2)×b)+y×sin(a+(n-1)×b); Step (D22), substitute the trigonometric identities and rearrange: sin(a+n×b)=[x×cos(2×b)+y×cos(b)]×sin(a+n×b)-[x×sin(2×b)+y×sin(b)]×cos(a+n×b); Step (D23), ensure that all n are true, solve the coefficient x=-1 of the recursive IIR filter, y=2×cos(b), it can be concluded that the calculation at each step angle increment only requires the y[-1] value to be moved into the y[-2] variable, and the calculated y[n] value to be moved into the y[-1] variable to prepare for the calculation at the next step angle.

3. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 1, characterized in that: In step (C2), For high priority alarms, the sequence is defined as a 5-note sequence that repeats once for a total of 10 notes; For medium priority alarms, the sequence is defined as a 3-note sequence, but without repetition; For low priority alarms, the sequence is defined as a 2-note sequence, but without repetition.

4. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 3, characterized in that: The high priority alarm has a faster beat than the medium priority alarm.

5. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 1, characterized in that: Step (E) specifically comprises the following steps: Step (E1), turn on the clock and set it as analog input; Step (E2), enabling the DAC clock; Step (E3), setting the DAC working mode; Step (E4), DAC output at 25ksps output rate.

6. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 1, characterized in that: In step (C2): the frequency, number and order of basic notes are set according to the alarm type and priority, where the high-level alarm is {C4, A4, F4, A4, F4} and the medium-level alarm is {C4, A4, F4, 0, 0}.

7. The method for synthesizing an audio alarm suitable for a medical electrical alarm system according to claim 1, characterized in that: In step (D2): a single fundamental note and four harmonic sine waves are generated, and then a multiple sine wave tones of the fundamental note and four harmonics are generated using the Goertzel algorithm.

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