JPH05720B2 - - Google Patents

Abstract

PURPOSE:To obtain automatically a proper output, by controlling an amplification factor of an output amplifier in accordance with the maximum amplitude of a stored sound. CONSTITUTION:An output amplifier gain controlling circuit 9 stores the maximum value of a sound signal converted to a digital signal, which is obtained from an encoding circuit 6. When reproducing a sound, the output amplifier gain controlling circuit 9 controls the gain of an amplifier 4 so that a sound outputted from a loudspeaker serving also as a microphone 3 is not saturated but can be heard with a large sound.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electronic watch with an audio function that has a function of encoding and recording and playing back externally input audio, and in particular, the amplification factor (hereinafter referred to as gain) of an output amplifier when outputting audio. Regarding the control method.

An object of the present invention is to provide a mechanism that can always obtain output audio at an appropriate level regardless of the magnitude of input audio.

Note that the term "sound" in this specification is used to include all sounds such as human voices, music, and imitation sounds.

In recent years, electronic watches have become increasingly multi-functional, and some have, for example, alarm and timer functions. However, the time reporting means for these functions is simply a sound specified by the manufacturer, and the user must use the given sound whether he likes it or not, and on top of that, he is always unsure what the sound is. I had the inconvenience of having to recognize and remember what it meant.
In order to eliminate this inconvenience, an electronic watch with a voice memory function is an electronic watch that has a voice memory function that allows the user to freely input necessary information from the outside by voice and output it as voice at an appropriate time. be.

Therefore, the volume of the input voice varies between individuals.
This is greatly influenced by differences in the environment, and if you only have an output amplifier with a fixed gain, if the input audio is too low, the output audio will be too low to be heard, and if the input audio is too loud, the amplifier output will saturate. The sound quality deteriorates and becomes unbearable to listen to. Furthermore, if the gain of the output amplifier is changed by operating a switch or the like, the operation becomes complicated, making the watch itself extremely difficult to handle, and adding a volume or the like increases the size.

In view of the above problems, the present invention provides a mechanism for controlling the gain of an output amplifier so as to eliminate this inconvenience and automatically obtain an appropriate output.Detailed explanation will be added below with reference to the drawings. .

FIG. 1 is a block diagram showing an example of the configuration of an electronic circuit of an electronic timepiece with a voice storage function according to the present invention.

In FIG. 1, 1 is an oscillation circuit that generates a reference clock signal, 2 is a frequency dividing circuit that receives the reference clock signal and generates necessary signals, and F ₁ to Fn
are various functional circuits such as a clock circuit and a display circuit. 3 is a microphone/speaker, and 4
It is connected to the I/O (input/output) switching circuit 5 through the amplifier system. The amplifier system No. 4 includes both an input amplifier and an output amplifier, and in particular, the output amplifier is configured so that its gain can be varied by receiving a control signal from a gain control circuit, which will be described later. Reference numeral 6 denotes an encoding circuit, which encodes the audio signal Voice given in an analog quantity into a digital quantity, and the signals encoded here are sequentially stored in the recording section 7.

Further, the recording section 7 is a semiconductor memory, for example.
It is mainly composed of a RAM (random access memory) and a shift register, and reading is performed based on the signal obtained from the frequency dividing circuit 2. 8 is an audio signal synthesis circuit;
This is a circuit that synthesizes an analog audio signal from the digital signal read out from the recording unit of No. 7. Reference numeral 9 denotes an output amplifier gain control circuit according to the present invention, which stores the maximum value of the audio signal encoded in a digital quantity obtained from the encoding circuit 6, and controls the output amplifier gain based on the data during audio reproduction. It is configured to determine the gain and output the control signal to the amplifier system.

FIG. 2 is a block diagram showing the configuration of an output amplifier gain control circuit according to the present invention.

In FIG. 2, 1 is a magnitude comparator, 2 is a recording section, and 3 is a gain control section. When audio is input, the output data of the encoding circuit (FIG. 1, 6) changes from time to time, so the magnitude comparator 1 compares the data stored in the storage section 2 with the current data. When it is determined that the input amplitude is larger in the current data, a command is output to the storage section, and the storage section erases the previous data and stores the current data. This operation continues until there is no more input voice, and therefore, finally, the data at the time of the maximum amplitude of the voice input this time is stored. After that, the gain control section 3 reads the maximum amplitude data, determines the gain of the output amplifier so that the maximum amplitude is closest to the full range (maximum output voltage) of the output amplifier at the time of output, and controls the control signal. Output. In addition, when inputting voice, reset the memory section in advance to erase the previous maximum value and initialize the data to the minimum value.

FIG. 3 shows the output audio when the input audio waveform is relatively small, where a shows the output gain fixed, and b shows the sound according to the present invention.

In FIG. 3, 1 is the output audio waveform, 2 is the bias point of the output amplifier, VDD represents the high potential of the power supply, Vss represents the low potential of the power supply, and point P is the peak point of this audio. In addition, in this example,
The encoding circuit shown in Fig. 16 converts the input audio waveform into 5-bit parallel data, and uses the 5th bit (B ₄ ) to represent plus or minus based on the bias point of 2 (B ₄ = 1). (indicates that it is negative with respect to the bias point). Since B0\ to _B3 are configured to represent the distance from the bias point, the output data is as shown in FIG.

Therefore, in this example, it is sufficient to compare the magnitudes of the 4-bit data B0\ to _B3 . Now, the third
Assuming that there is an input audio waveform as shown in the figure, the storage section in Figure 2 will contain 0\0\0\0\(B ₃ ~ B0\) →...
→
It is stored in the order of 0\10\0\→…→0\111→…→10\10\, and finally 1010 is stored. Here, when the output gain is fixed, the output gain is full when the data is 1111.
Since the gain is determined to match the range (the gain at this time is expressed as GMIN), only an output of 11/16 of the full range can be obtained as shown in a, and the output audio will be low. However,
According to the present invention, the gain control section shown in FIG. 2 detects the maximum data 10\10\ and automatically adjusts the gain.
Since the gain of the output amplifier is controlled to be 16/11 times GMIN, the output audio is as shown in b.
Since the full range of the output amplifier is output without saturation, it can be heard clearly even at loud volumes.

FIG. 4 shows a specific example of the configuration of the output amplifier gain control circuit according to the present invention shown in the block diagram in FIG.

In FIG. 4, 1 inside the double-dashed line frame is a 4-bit magnitude comparator, which is composed of a NAND gate and an AND gate, and 2 inside the double-dashed line frame is a storage section.
It consists of two master-slave type F/Fs (flip-flops), and 3 inside the dashed line frame is the gain control section, which includes an inverter, an AND gate, and a NOR
It consists of a gate and an EXCLUSIVE-NOR gate. Furthermore, B ₀ to _{B 3} are the outputs of the encoding circuit of FIG. 16, and are shown in FIG. 3.

Further, the signal Reset is used to reset the storage section 2 and perform initial settings. Now, when audio is input, B0\~ _B3 changes every moment, and the magnitude comparator 1 constantly compares this data with the maximum value data Q0\~ _Q3 stored in the storage section 2. ,
If B0\~ _B3 is large, the output CL will be set to logic level "HI"
Make it. The F/F of the storage section stores B0\~ _B3 connected to each D terminal at the rising edge,
Output the data to Q0\~ _Q3 . Therefore, B
Since 0\~B ₃ and Q0\~Q ₃ match, the output CL becomes the logic level "LO", and the above operation is repeated, and finally the maximum value data of the current audio is stored in the storage unit 2. is memorized. The stored maximum value data Q0\~ _Q3 is data converted by the gain control unit 3,
A variable gain type is output as a gain control signal C0\ to _C3 . In this example, the gain control section takes the stability of the output amplifier into account and performs control so that the gain is not set to more than 16/4 times GMIN. In addition,
The amplifier controlled in this example is controlled by C0\~ _C3 .
The configuration is such that the gain is varied by 16/(C ₀ +2C ₁ +4C ₂ +8C ₃ ) times GMIN.

As described above, according to the present invention, the user only needs to generate audio toward the clock without any troublesome operations, and the audio output voice can be made loud and clear. becomes possible.

Furthermore, since the present invention can be easily integrated into an integrated circuit, it can be particularly effective for electronic devices such as wristwatches that are required to be small and easy to operate.

Furthermore, since the input voice is directly stored without any processing at the time of input, there is no need for registers or high-speed calculation means to specially process the input voice, and the circuit system can be significantly reduced.

Furthermore, since it is only necessary to set the amplification factor on the output amplifier once before outputting the audio in accordance with the maximum value of the input audio, the number of processing steps is reduced and it also contributes to lower power.

[Brief explanation of drawings]

FIG. 1: An example of the configuration of an electronic circuit of an electronic timepiece with voice memory according to the present invention. FIG. 2: A configuration block diagram of an output amplifier gain control circuit according to the present invention. Third
Figure a: Output audio waveform when the output amplifier gain is fixed. b...Output audio waveform according to the present invention. Figure 4...
...Specific configuration example of the output amplifier gain control circuit according to the present invention.

Claims (1)

[Scope of Claims] 1. Consisting of at least a recording mechanism that encodes and records and stores audio input from the outside, an output mechanism consisting of a linear amplifier with a variable amplification factor, and an output amplifier gain control mechanism that controls the output mechanism, The output amplifier gain control circuit includes a comparator, a storage section, and an amplification factor control section, and the comparator compares the input audio and the code stored in the storage section to determine the input audio. is determined to be large, outputs a signal to the storage unit, the storage unit stores data at maximum amplitude based on the output from the comparator, and the amplification factor control unit outputs a signal to the storage unit An electronic device with a voice storage function, characterized in that the amplification control of the linear amplifier is performed based on.