JPH04189035A - Gain control circuit for receiver - Google Patents

Abstract

PURPOSE:To use the optimum state by measuring a maximum input signal level, a saturation output level of a pre-stage power amplifier and each stage noise figure and controlling the gain of the power amplifier so as to optimize the receiver noise figure and the dynamic range. CONSTITUTION:A noise figure measurement circuit 2 measures noise figures NFa(T), NFb(T) of power amplifiers 8-a, 8-b at an ambient temperature T, and a signal level measurement circuit 3 measures a maximum input signal level PinMAX(T) of a receiver 7 and a saturation output level P-1a of the amplifier 8-a. An arithmetic circuit 4 calculates a gain Ga of the amplifier 8-a so as to minimize a function F (=WNFDELTANF+WpinDELTAPinMAX) based on initial values NF(T0), PinMAX(T0) of a reception noise figure and a maximum input signal level of the receiver 7 stored in a memory 5, on an insertion loss L and waiting factors WNP, Wpin of other circuit element 9 and on a measured data of the circuits 2,3. A control circuit 6 controls the gain of the amplifier 8-a in response to the result of the calculation of the circuit 4 to obtain a proper reception.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a gain control circuit for a receiver, and particularly to a gain control circuit for a receiver.
The present invention relates to a gain control circuit for a receiver including a stage power amplifier.

[Conventional technology]

Conventionally, in a receiver that includes two or more stages of power amplifiers, it is necessary to satisfy the reception noise figure and reception dynamic range required of the receiver based on the performance of the power amplifiers and other circuit elements in each stage that make up the receiver. As such, the gain of each stage of the power amplifier was set in advance.

[Problems to be Solved by the Invention] In the conventional receiver described above, the gain of the power amplifier at the front stage decreases due to changes in ambient temperature, the gain of the power amplifier at the front stage is suppressed by AGC, and the power amplifier at the rear stage decreases. The overall reception noise figure of the receiver increases due to the noise generated by the receiver.

In order to eliminate deterioration of the receiver's overall reception noise figure, if the gain of the front-stage power amplifier is set large at high temperatures, the gain of the front-stage power amplifier at low temperatures increases, and one of the multiple power amplifiers Since the output of the receiver reaches a saturation level, the reception dynamic range deteriorates and the maximum receivable signal level decreases. Therefore, there is a drawback that the reception noise figure and reception dynamic range of the receiver cannot always be maintained in an optimal operating state with respect to the ambient temperature.

Therefore, it would be extremely effective if there were a receiver gain control circuit that could overcome the above drawbacks.

SUMMARY OF THE INVENTION An object of the present invention is to provide a gain control circuit for a receiver that can always maintain optimal reception noise figure and reception dynamic range.

A gain control circuit for a receiver according to the present invention includes at least two stages of power amplifiers, a noise figure measuring circuit for measuring the noise figure of each of these power amplifiers, and a gain control circuit for a receiver according to the present invention. and a signal level measuring circuit for measuring the saturated output level of the power amplifier in the preceding stage, a memory for storing the total noise figure and the maximum input signal level in a predetermined standard state, and the noise figure measuring circuit and the signal level measuring circuit. an arithmetic circuit that calculates the gain of at least the preceding power amplifier in order to set the reception dynamic range and the total reception noise figure to optimal values using the measured data of the circuit and the stored contents of the memory; and a control circuit that controls the gain of at least the preceding power amplifier based on the calculated gain.

Further, the gain control circuit of the receiver of the present invention stores reception dynamic weights and total noise figure weights in the memory, and the arithmetic operation circuit stores reception dynamic weights and total noise figure weights in the memory.

At least the gain of the power amplifier in the previous stage is adjusted so that the amount obtained by multiplying the watercress deterioration JL by the weight of the reception dynamic range and the amount obtained by multiplying the deterioration of the total noise figure by the weight of the total noise figure are minimized. may be configured to calculate.

=Example] Next, the present invention will be explained with reference to the drawings.

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

The gain control circuit 1 is composed of a noise figure measuring circuit 2, a signal level measuring circuit 3, an arithmetic circuit 4 including a memory 5, and a control circuit 6.

Reception noise figure N at ambient temperature T of receiver 7 composed of power amplifiers 8-a, 8-b and other circuit elements 9
F (T) and maximum input signal level PinMAX (T)
is Ij a Ulsu/is. However, NFx(T): Noise figure (x- a, b) of power amplifier 8-x at ambient temperature T; Gx(T): Noise figure of power amplifier 8-x at ambient temperature T.
/gain (x=a.

b) P-+x(T)' power amplifier 8-x at ambient temperature T
Saturation output level - (x-a, b) L: Insertion loss of other circuit elements 9. At ambient temperature T = T, the maximum input signal level P inMAX (To) of the receiver is the power amplifier 8 - When the saturation output level P, -+a(To) of the receiver 7 is suppressed, the reception noise figure NF(T,) and the maximum input signal level P inMAX(T o) of the receiver 7 are as follows. The level tire crumb will look like the solid line ■ in Figure 2.

When the ambient temperature T rises to T=To+ΔT (ΔT>0), the gains of the power amplifiers 8-a and 8-b decrease and the noise figure increases, so the reception noise figure of the receiver 7 becomes N F
(T) becomes larger. On the other hand, the decrease in the saturation level output of the power amplifier is less than the decrease in the gain, the level diagram becomes as shown by the solid line (■) in FIG. 2, and the maximum input signal level PinMAX(T) of the receiver increases. That is, NF(T, +ΔT)=NFa(T*+ΔT)Ga(T+
+ΔT) P inMAX(To) −(6) Here, the maximum input signal level of the receiver 7 is P inMA
X: = PinMAX(To)
-(7), set the gain Ga of the power amplifier 8-a to Ga (T)20a as shown by the broken line in FIG.
If you raise it to
・(8) NFX(To+ΔT)>NFX(
TO) (x=a, b) - (9:1), so if the reception noise figure of the receiver 7 at this time is NF, then from equations (1), (3), and (7), NF ( T
o+ΔT)>NF,>NF(T.) −(1
0). Also, the reception noise figure of receiver 7 is NF2=N
If the gain Ga of the power amplifier 8-a is increased by Ga (T) = Ga 2 as shown by the dashed line in Fig. 2 so that F(Tc) - (ID), then the receiver at this time becomes The maximum input signal level PinMAX2 of 7 is P+nMAXz <P+nM, AX(To)
−(12).

From the above explanation, while increasing the gain Ga of the power amplifier 8-a from Ga1 to Ga2 at the ambient temperature T=To+ΔT, the reception noise figure of the receiver becomes N F +(
> NF(To)) to NF l (= NF C'r
,,))), while the maximum input signal level is PinMAX.

C” P inMAXCT o) ) to P inMA
X, (< P inMAX (Ti)).

Here, the reception noise figure NF(To) of the receiver at the ambient temperature T=To, the maximum input signal level P inMAX(
F''
WNFΔNF+WP,,ΔP inMAX
-03), F is a function of the gain Ga of the power amplifier 8-a, and there exists a value of Ga such that F becomes the minimum.

At the ambient temperature T, the noise figure measuring circuit 2 is connected to the power amplifier 8.
-a, 8-b noise figure NFa(T).

N F b (T) is measured, and the signal level measurement circuit 3 measures the maximum input signal level P inMAX (T) of the receiver 7 and the saturated output level P-, a (T) of the power amplifier 8-a.

The arithmetic circuit 4 calculates the initial value NF(T,) of the reception noise figure of the receiver 7 and the maximum input signal level stored in the memory 5.
and P InMAX(T o) and the insertion loss of other circuit elements 9 and weight, ink W, , W,. Then, calculate the gain Ga of the power amplifier 8-a that minimizes the value of the function F expressed by equation (13) from the measurement data of the noise figure measurement circuit 2 and the S-bell measurement circuit 3. do.

The control circuit 6 receives the result calculated by the arithmetic circuit 4, and controls the gain of the power amplifier 8-a accordingly.

Note that the gain of the power amplifier 8-b may also be controlled, and the arithmetic circuit 4 and the control circuit 6 may be configured to control the gain of the power amplifier 8-b in response to control of the gain of the power amplifier 8-a. I can bring it.

[Effects of the Invention] As explained above, the present invention provides a receiver including at least two stages of power amplifiers with a maximum input signal level that changes with changes in ambient temperature and a saturation output of the power amplifier in the previous stage. Measure the level and noise figure of each stage, calculate the gain of the power amplifier that provides the optimal combination of the reception noise figure and reception dynamic range of the receiver, and use the calculated gain to determine the gain of the front power amplifier. By controlling this, the combination of the reception noise figure of the receiver and the reception dynamic lens can be used in an optimal operating state at all times in response to fluctuations in ambient temperature.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of one embodiment of the present invention, and FIG. 2 is a block diagram of an embodiment of the present invention.
This is a level diagram of the receiver 7 in the figure. 1...gain control circuit, 2...noise figure measurement circuit, 3...signal level measurement circuit, 4...
Arithmetic circuit, 5...Memory, 6...Control circuit, 7...Receiver, 8-a, b...Power amplifier, 9... Other circuit elements. Agent: Patent Attorney Shinya Uchihara

Claims (1)

[Claims] 1. At least two stages of power amplifiers, a noise figure measuring circuit that measures the noise figure of each of these power amplifiers, and measures the maximum input signal level and the saturation output level of the power amplifier in the preceding stage. a signal level measuring circuit that stores the overall noise figure and the maximum input signal level in a predetermined standard state; and a memory that stores the measured data of the noise figure measuring circuit and the signal level measuring circuit and the storage contents of the memory. an arithmetic circuit that calculates the gain of the power amplifier in at least the preceding stage in order to set the reception dynamic range and the total reception noise figure to optimal values using the calculation circuit; A gain control circuit for a receiver, comprising: a control circuit for controlling a gain of a receiver. 2. The weight of the reception dynamic range and the weight of the total noise figure are stored in the memory, and the arithmetic circuit calculates the amount obtained by multiplying the amount of deterioration of the reception dynamic range by the weight of the reception dynamic range and the deterioration of the total noise figure. 2. The gain control circuit for a receiver according to claim 1, wherein the gain of at least the preceding power amplifier is calculated so that the sum of the total noise figure and the weighted amount is minimized.