JP2001211125A - Detector circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a detector circuit which has high precision and a wide dynamic range by combining a detector circuit which has a narrow dynamic range and high resolution and a detector circuit which has a wide dynamic range and low resolution together. SOLUTION: This circuit is equipped with a 1st detector circuit 14 which has a narrow dynamic range and high resolution, a 2nd detector circuit 12 which has a wide dynamic range and low resolution, an input level varying circuit 14 which varies the input level of the 1st detector circuit, and a control circuit 13 which controls the level variation quantity of the input level varying circuit with the detection output of the 2nd detector circuit, and the control circuit controls the input level varying circuit based on the detection output of an input signal detected by the 2nd detector circuit so that the input level of the 1st detector circuit has a specific dynamic range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a detection circuit used for a transmitting device or a receiving device.

[0002]

2. Description of the Related Art Conventionally, a detection circuit of a transmission apparatus or a reception apparatus has been constituted by either a thermal detection circuit or an RSSI detection circuit. The thermal detection circuit has a disadvantage that a dynamic range used for detection of an input signal is low, and sensitivity and speed at the time of detection are low. However, since it has an advantage of high resolution, a highly accurate detection output can be obtained.

Further, the RSSI detection circuit has a high sensitivity to an input signal, so that a detection output can be obtained with a quick response, and furthermore, it has an advantage that a dynamic range used for detection is high, but has a disadvantage that resolution is low. have.

In the conventional example, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 0481, in a signal of a certain constant level, it is possible to suppress a detection output error due to manufacturing variations and aging of elements used for detecting the signal, and to obtain a highly accurate detection output. , Only a thermal detection circuit.

[0005]

However, in a thermal detection circuit, for example, when detecting a signal having a dynamic range of 20 dB or more, it is necessary to detect the signal in a range of 20 dB or more. As a rough guide, there is a problem that a dynamic range of only 20 dB can be obtained.

In an RSSI detection circuit, for example,
The detection method of the SI detection circuit is envelope detection. Therefore, when a signal whose amplitude fluctuates greatly, such as a modulated wave, there is a problem that a detection output error increases.

The present invention has been made to solve such a conventional problem, and has a narrow dynamic range and high resolution detection circuit such as a thermal detection circuit, and a wide dynamic range such as an RSSI detection circuit. An object of the present invention is to provide a high-accuracy and wide dynamic range excellent detection circuit by combining with a low-resolution detection circuit.

[0008]

A detection circuit according to the present invention comprises a first detection circuit having a high resolution in a narrow dynamic range, a second detection circuit having a low resolution in a wide dynamic range, and a first detection circuit. An input level variable circuit for varying an input level of the circuit; and a control circuit for controlling a level variable amount of the input level variable circuit by a detection output of the second detection circuit, wherein the control circuit includes an input level of the first detection circuit. Has a configuration in which the input level variable circuit is controlled based on the detection output of the input signal detected by the second detection circuit so that the input signal has a predetermined dynamic range.

With this configuration, the control circuit controls the variable level of the input level variable circuit by the detection output of the second detection circuit so that the input level of the first detection circuit has a predetermined dynamic range. One detection circuit can detect a wide dynamic range by repeating high-precision detection in a narrow dynamic range.

Further, the detection circuit of the present invention has A / D conversion means for outputting the detection output of the first detection circuit and the control output of the control circuit as digital values.

According to this configuration, the detection output of the first detection circuit and the control output of the control circuit are digitally output, and the digital control output is added to the digital detection output to thereby provide the first detection circuit with a digital control output. By using the dynamic range repeatedly, a highly accurate detection output can be obtained in a wide dynamic range.

Further, the detection circuit of the present invention has an addition circuit for adding a voltage value corresponding to a control output from the control circuit and a detection output from the first detection circuit.

With this configuration, by adding the control output output from the control circuit and the detection output output from the second detection circuit, an almost linear analog detection output can be obtained in a wide dynamic range. it can.

Further, the control circuit in the detection circuit of the present invention, wherein the detection output of the first detection circuit is input and the detection output of the second detection circuit is near the threshold of the input level variable circuit,
It has a configuration used for switching determination in the input level variable circuit.

With this configuration, when the detection output of the second detection circuit is near the threshold for switching the input level variable circuit, the control circuit uses the detection output of the first detection circuit to determine the switching of the input level. The output can be prevented from fluttering without switching the circuit unnecessarily, and a stable detection output can be obtained.

Further, the detection circuit of the present invention has a configuration in which switch means is provided in a preceding stage of the input level variable circuit, and the switch means is controlled by a control circuit.

With this configuration, the control circuit controls the switch means in accordance with the output of the second detection circuit, and can prevent the first detection circuit from being damaged even if the input signal becomes excessively input, As long as the excessive input does not continue for a certain time, the detection can be performed again in the first detection circuit.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to FIGS.

(Embodiment 1) FIG. 1 is a block diagram showing Embodiment 1 of a detection circuit according to the present invention. 1, the detection circuit 1 includes an input terminal 11, an RSSI detection circuit 12, a control circuit 13, an input level variable circuit 14, a thermal detection circuit 15, a control output terminal 16, and a detection output terminal 17.

The RSSI detection circuit 12 is a second detection circuit that detects the level of an input signal input from the input terminal 11 and outputs a detection output to the control circuit 13.

The control circuit 13 controls the level variable amount of the input level variable circuit 14 based on the detection output from the RSSI detection circuit 12 and outputs a discrete voltage value corresponding to the level variable amount from the control output terminal 16. I do.

The input level variable circuit 14 has a level variable amount controlled by the control circuit 13, and discretely varies the level of an input signal input from the input terminal 11 to the thermal detection circuit 15, for example, variable attenuation. A device or a variable gain amplifier is used.

The thermal detection circuit 15 is a first detection circuit that detects a signal output from the input level variable circuit 14 and obtains a substantially linear output with respect to input power within a predetermined dynamic range. The detected signal is output from a detection output terminal 17.

Next, the operation of the detection circuit 1 will be described with reference to the input / output characteristic diagrams shown in FIGS. First, the level of the signal input to the thermal detection circuit 15 is
As shown in FIG. 2, if the dynamic range is within 20 dB, the detection output is output almost linearly with respect to the input signal. However, if the level of the input signal is outside this dynamic range, the detection output will be saturated,
An accurate detection output cannot be obtained from the detection output terminal 17.

Therefore, RSS having a wide dynamic range is used.
The I detection circuit 12 detects the input signal input to the input terminal 11, receives the detection output, controls the level variable amount of the input level variable circuit 14 by the control circuit 13, and inputs the input signal to the thermal detection circuit 15. The signal level is adjusted so as to be within the dynamic range of the thermal detection circuit 15.

As a result, even if the level of the input signal inputted from the input terminal 11 is out of the dynamic range of the thermal detection circuit 15, the level of the input signal is shown in FIG. By switching discretely in this way, even a signal whose input level fluctuates greatly, such as a modulated wave, can be adjusted to an appropriate level. In this manner, as shown in FIG. 4, the thermal detection circuit 15 can perform substantially linear detection over a wide range by repeatedly using the dynamic range of the thermal detection circuit 15.

(Embodiment 2) FIG. 5 is a block diagram showing Embodiment 2 of a detection circuit according to the present invention. As shown in the figure, a detection circuit 2 is an A / D conversion circuit that converts a voltage value according to a level variable amount output from a control circuit 13 into a digital value in addition to the configuration of the detection circuit 1 shown in FIG. 1
8 and an A / D conversion circuit 19 for converting a detection output output from the thermal detection circuit 15 into a digital value.

In this configuration, the detection circuit 2 can digitally output the variable level from the control output terminal 16. Finally, in the overall control of the detection circuit 2, for example, a digital value at the detection output terminal 17 is compared with a digital value at the control output terminal 16, for example, “000”, “001”,. Is added, and as a result, detection is performed by repeatedly using the dynamic range of the thermal detection circuit 15, and a wide dynamic range,
A highly accurate detection output can be obtained.

(Embodiment 3) FIG. 7 is a block diagram showing Embodiment 3 of a detection circuit according to the present invention. As shown in the figure, the detection circuit 3 has a voltage value corresponding to the level variable output from the control circuit 13 and an output from the thermal detection circuit 15 in addition to the configuration of the detection circuit 1 shown in FIG. An addition circuit 20 for adding the detection output and an addition circuit output terminal 21 are provided.

In this configuration, the detection circuit 3 uses an addition circuit 20 to add a discrete voltage value corresponding to the level variable output from the control circuit 13 and a detection output output from the thermosensitive detection circuit 15. The signals are added and output to the addition circuit output terminal 21. As a result, an almost linear analog detection output can be obtained in a wide dynamic range with respect to the input level as shown in FIG.

(Embodiment 4) FIG. 9 is a block diagram showing a detection circuit according to Embodiment 4 of the present invention. As shown in the figure, the detection circuit 4 includes input means 22 for inputting the output of the thermal detection circuit 15 to the control circuit 13 in addition to the configuration of the detection circuit 1 shown in FIG.

In this configuration, the detection circuit 4 inputs the output of the thermal detection circuit 15 to the control circuit 13 and uses the output of the RSSI detection circuit 14 for switching determination when the detection output of the RSSI detection circuit 14 is near the threshold value of the input level variable circuit 12. I have.

For example, when the dynamic range is switched from the region a to the region b in the input / output characteristic diagram shown in FIG. 11, when the dynamic range of the thermal detection circuit 15 is 20 dB in the input / output characteristic diagram shown in FIG. A
, The detection is actually performed using the central area B (dynamic range 15 dB), and when the detection output falls within the area C (2.5 dB) above the dynamic range, the input level variable circuit 14 Switch.

When the dynamic range is switched from the area b to the area a shown in FIG. 11, the same switching is performed using the detection output within the range D (2.5 dB) below the dynamic range. . Further, when the dynamic range is switched in two or more steps, such as from the area a to the area c or from the area c to the area a, RS
Switching is performed using information of the SI detection circuit 12.

As described above, the output of the thermal detection circuit 15 is input to the control circuit 13, and when the detection output of the RSSI detection circuit 12 is near the threshold of the input level variable circuit 14, the outputs of the two detection circuits are changed to the input level. By performing control using the switching in the variable circuit 14, the input level variable circuit 14 is not switched indiscriminately, so that the output can be prevented from fluttering and a stable detection output can be obtained.

(Embodiment 5) FIG. 12 is a block diagram showing Embodiment 5 of a detection circuit according to the present invention. As shown in the figure, the detection circuit 5 includes a switch 23 controlled by the control circuit 13 at a stage preceding the input level variable circuit 14 in addition to the configuration of the detection circuit 4 shown in FIG.

In this configuration, the detection circuit 5 uses the RSSI
Input level variable circuit 1 according to the detection output of detection circuit 12
4 is set to the maximum variable amount. If the input signal exceeds the input level range of the thermal detection circuit 15, the control circuit 13 determines that the input is excessive, and the switch 23 is turned off instantaneously and the thermal detection circuit 15 is turned off. The detection circuit 15 can be protected.

Further, in the RSSI detection circuit 12,
Subsequently, the input signal is detected. If the control circuit 13 determines that the input signal is not excessively input, the switch 23 is turned on so that the detection circuit 5 can detect the input signal again.

As described above, when the input signal is over-input, the thermal detection circuit 15 can be prevented from being damaged. Unless the input is continued for a certain period of time, the thermal detection circuit 15 is re-input.
Can be detected.

[0040]

As described above, according to the present invention, the input level of the first detection circuit (thermal detection circuit) is discretely switched according to the detection output of the second detection circuit (RSSI detection circuit). Thus, it is possible to obtain a detection circuit capable of detecting various modulated waves with high accuracy and a wide dynamic range. For example, even in the case of a modulated wave whose level varies by 20 dB or more, the gain of the transmission amplifier can be kept constant or the output-constant control can be performed with high accuracy.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of a detection circuit according to the present invention;

FIG. 2 is an input / output characteristic diagram illustrating the operation of the first embodiment.

FIG. 3 is an input / output characteristic diagram illustrating the operation of the first embodiment.

FIG. 4 is an input / output characteristic diagram illustrating the operation of the first embodiment.

FIG. 5 is a block diagram showing a detection circuit according to a second embodiment of the present invention;

FIG. 6 is an input / output characteristic diagram illustrating the operation of the second embodiment.

FIG. 7 is a block diagram showing a detection circuit according to a third embodiment of the present invention;

FIG. 8 is an input / output characteristic diagram illustrating the operation of the third embodiment.

FIG. 9 is a block diagram showing a detection circuit according to a fourth embodiment of the present invention;

FIG. 10 is an input / output characteristic diagram of a thermal detection circuit illustrating the operation of the fourth embodiment.

FIG. 11 is an input / output characteristic diagram of an RSSI detection circuit illustrating the operation of the fourth embodiment.

FIG. 12 is a block diagram showing a detection circuit according to a fifth embodiment of the present invention;

[Explanation of symbols]

 1, 2, 3, 4, 5 detection circuit 11 input terminal 12 RSSI detection circuit 13 control circuit 14 input level variable circuit 15 thermal detection circuit 16 control output terminal 17 detection output terminal 18, 19 A / D conversion circuit 20 addition circuit 21 Adder circuit output terminal 22 Input means 23 Switch

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) 5J100 AA02 AA03 AA16 BA10 BB15 BC07 CA11 DA06 EA02 FA01 FA02 5K042 CA11 CA12 DA12 DA16 EA03 FA01 FA29 GA01 JA01 JA03 LA03 NA04 5K060 HH03 HH08 JJ23 LL01 LL24 5K061 A06 CC

Claims (5)

[Claims] A first detection circuit having a narrow dynamic range and high resolution; a second detection circuit having a wide dynamic range and low resolution; and an input level variable for varying an input level of the first detection circuit. And a control circuit for controlling a level variable amount of the input level variable circuit by a detection output of the second detection circuit, wherein the control circuit is configured such that an input level of the first detection circuit is a predetermined dynamic range. A detection circuit for controlling the input level variable circuit based on a detection output of an input signal detected by the second detection circuit. 2. An A / A for outputting a detection output of the first detection circuit and a control output of the control circuit as digital values.
2. The detection circuit according to claim 1, further comprising D conversion means. 3. The detection circuit according to claim 1, further comprising an addition circuit for adding a voltage value according to the control output from the control circuit and a detection output from the first detection circuit. 4. The control circuit receives a detection output of the first detection circuit, and switches the input level variable circuit when a detection output of the second detection circuit is near a threshold value of the input level variable circuit. 2. The detection circuit according to claim 1, wherein the detection circuit is used for determination. 5. The detection circuit according to claim 1, wherein switch means is provided in a preceding stage of said input level variable circuit, and said switch means is controlled by said control circuit.