JPH05235786A - Transmission level control circuit - Google Patents

Abstract

PURPOSE:To automatically correct an error due to a temperature characteristic or an error or the like due to dispersion in components by automatically correcting a control variable so that an output of a transmission level detector reaches an expected value. CONSTITUTION:An output of a variable resistor 8 used to generate a very small address level is given to an A/D converter 7, in which the level is A/D- converted and an output of the A/D converter 7 is inputted to a sub CPU 1 through a bug. A transmission level detector 6 detects a current transmission level and an output of the transmission level detector 6 is inputted to an A/D converter 5, in which the signal is A/D-converted and the output of the A/D converter 5 is inputted to the sub CPU 1 through a bus. The sub CPU 1 subtracts the current transmission level detection value being an output of the A/D converter 5 from the sum of the a digital level corresponding to a level of a transmission analog signal from a main CPU 2 and the transmission level fine-adjusted value being an output of the A/D converter 7 and adds the result to the current input of a D/A converter 3 as a new input of the D/A converter 3. A transmission level controller 4 changes the transmission level based on the output of the D/A converter 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention is used in mobile radio communication devices and other analog signal transmitting devices. In particular, it relates to a means for automatically correcting an error due to temperature characteristics or the like in the transmission level control circuit.

[0002]

2. Description of the Related Art A conventional transmission level control circuit does not correct an error due to a temperature characteristic or an element variation.

[0003]

The conventional transmission level control circuit as described above has a drawback that an error occurs in the transmission level due to an error due to a temperature characteristic, an error due to element variation, and the like.

The present invention eliminates such drawbacks, and an object of the present invention is to provide a transmission level control circuit having means for automatically correcting an error due to temperature characteristics, an error due to element variation, and the like. .

[0005]

SUMMARY OF THE INVENTION The present invention is a transmission level control circuit connected to a transmission level controller for adjusting the level value of an analog signal being transmitted according to a given analog signal. Level value setting means for setting a digital level value corresponding to the level value of
A transmission level detector that detects the current value of the level of the analog signal being transmitted, a first conversion means that converts the level value of the analog signal detected by this transmission level detector into a digital level value, and a minute analog level Adjusting value generating means for generating a value, second converting means for converting the minute analog level value generated by the adjusting value generating means into a digital level finely adjusting value, and a given digital signal for converting into an analog signal. Calculating the sum of the digital level value set by the level value setting means and the digital level fine adjustment value converted by the second converting means. The difference between the value and the digital level value converted by the first converting means is calculated, and the calculated value and the digital value currently converted by the third converting means. It calculates the sum of the signal, the calculated value, characterized in that a calculation means for providing a new digital signal to said third conversion means.

Here, the level value setting means and the arithmetic means may be CPUs.

[0007]

[Operation] The control amount of the transmission level controller is automatically corrected so that the output value of the transmission level detector becomes the expected value,
Automatically corrects transmission level errors due to errors due to temperature characteristics and due to element variations.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the configuration of this embodiment. As shown in FIG. 1, this embodiment includes a transmission level controller 4 that adjusts the level value of the analog signal being transmitted according to a given analog signal, and further,
As a feature of the present invention, a main CPU 2 which is a level value setting means for setting a digital level value corresponding to the level value of the analog signal to be transmitted, and a transmission level for detecting the current value of the level of the analog signal being transmitted. Detector 6
An AD converter 5 which is a first converting means for converting the level value of the analog signal detected by the transmission level detector 6 into a digital level value, and an adjustment value generating means for generating a minute analog level value. The variable resistor 8 and the second converting means A for converting the minute analog level value generated by the adjusting value generating means into the digital level fine adjusting value.
A D converter 7, a DA converter 3 which is a third converting means for converting a given digital signal into an analog signal and giving it to the transmission level controller 4, and a digital level value set by the level value setting means. The sum of the digital level fine adjustment value converted by the second converting means is calculated, and the difference between the calculated value and the digital level value converted by the first converting means is calculated. The sub-CPU 1 is a computing means for computing the sum of the digital signal currently converted by the three converting means and giving the calculated value as a new digital signal to the third converting means.

Next, the operation of this embodiment will be described. The transmission level is designated from the main CPU 2 to the sub CPU 1. The variable resistor 8 is for finely adjusting the transmission level value by the main CPU 2, and the output of the variable resistor 8 is A
It is input to the D converter 7 and AD-converted, and the output of the AD converter 7 is input to the sub CPU 1 through the bus. The transmission level detector 6 detects the current transmission level value, the output of the transmission level detector 6 is input to the AD converter 5 and AD-converted, and the output of the AD converter 5 is output to the sub CPU 1 through the bus.
Entered in. The sub CPU 1 calculates the difference between the sum of the transmission level value by the main CPU 2 and the transmission level fine adjustment output from the AD converter 7 and the current transmission level detection value output from the AD converter 5 in the current DA converter 3. The input to the new DA converter 3 is added to the input. Transmission level controller 4
Changes the transmission level value according to the output of the DA converter 3.

[0010]

As described above, according to the present invention, the transmission level detection value output from the AD converter 5 is the main CPU 2
Since it is possible to adjust the input of the DA converter 3 which is the control amount of the transmission level controller 4 so as to be equal to the sum of the transmission level designation value from the above and the transmission level fine adjustment value which is the output of the AD converter 5. In addition, it is possible to automatically correct an error in the transmission level due to an error due to temperature characteristics, an error due to element variation, and the like.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

[Explanation of symbols]

 1 Sub CPU 2 Main CPU 3 DA Converter 4 Transmission Level Controller 5 AD Converter 6 Transmission Level Detector 7 AD Converter 8 Variable Resistor

Claims (2)

[Claims] 1. A transmission level control circuit connected to a transmission level controller for adjusting the level value of an analog signal being transmitted according to a given analog signal, wherein a digital level corresponding to the level value of the analog signal to be transmitted. Level value setting means for setting a value, a transmission level detector for detecting the current value of the level of the analog signal being transmitted, and a level value of the analog signal detected by this transmission level detector is converted into a digital level value. First conversion means, adjustment value generation means for generating a minute analog level value, second conversion means for converting the minute analog level value generated by the adjustment value generation means into a digital level fine adjustment value, The conversion means converts the digital signal into an analog signal and gives it to the transmission level controller, and third level conversion means and the level value setting means. The sum of the digital level value thus converted and the digital level fine adjustment value converted by the second converting means, and the difference between the calculated value and the digital level value converted by the first converting means, And a calculating means for calculating the sum of the calculated value and the digital signal currently converted by the third converting means, and giving the calculated value to the third converting means as a new digital signal. And a transmission level control circuit. 2. The transmission level control circuit according to claim 1, wherein the level value setting means and the computing means are CPUs.