JPH0525848U - Integrated circuit for China - Google Patents

Abstract

(57) [Summary] [Configuration] VHF amplifier circuit 7 (or UHF amplifier circuit 1
A part of the output of 1) is taken out as a PLL sampling signal, which is amplified and output by the PLL amplifier circuit 20. [Effect] The PLL sampling signal is applied to the VHF resonance circuit 1
6 (or UHF resonance circuit 19) is not directly taken out, the operation of the resonance circuit or the oscillation circuit can be stabilized.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a tuner integrated circuit which receives a VHF band or UHF band high frequency signal, converts the high frequency signal into an intermediate frequency signal, and outputs the intermediate frequency signal.

[0002]

[Prior Art]

 FIG. 3 is a conventional example shown in a block diagram. The inside of a dotted line frame shows an integrated circuit for a tuner (hereinafter, the integrated circuit is abbreviated as “IC”), and the outside of the dotted line frame shows an IC peripheral circuit. Represent. The configuration and operation of the conventional example FIG. 3 will be described below. Reference numeral 1 denotes an input terminal for a VHF / UHF switching signal. For example, when receiving a VHF high frequency signal (hereinafter, the high frequency signal is abbreviated as "RF signal"), a low level switching signal is input to receive the UHF RF signal. At this time, a high level switching signal is input. Reference numeral 2 is a VHF RF signal input terminal, and reference numeral 3 is a UHF RF signal input terminal. Reference numeral 4 denotes a VHF / UHF switching circuit, which receives a VHF / UHF switching signal from the terminal 1, and when receiving the VHF RF signal, activates the VHF RF amplification circuit 8, the VHF oscillation circuit 6, and the VHF amplification circuit 7, The UHF RF amplifier circuit 9, the UHF oscillator circuit 13, and the UHF amplifier circuit 11 are put into a non-operating state. When receiving the UHF RF signal, the VHF RF amplification circuit 8, the VHF oscillation circuit 6, and the VHF amplification circuit 7 are set in the non-operating state, and the UHF RF amplification circuit 9, the UHF oscillation circuit 13, and the UHF amplification circuit 11 are set in the operating state. To do.

Reference numeral 5 is a connection terminal between the VHF resonance circuit 16 and the VHF oscillation circuit 6. Reference numeral 6 is a VHF oscillation circuit for generating a VHF oscillation signal for converting the VHF RF signal into an intermediate frequency signal (hereinafter, the intermediate frequency is abbreviated as "IF"). A VHF amplifier circuit 7 amplifies the VHF oscillation signal generated in the VHF oscillation circuit 6. A VHF amplifier circuit 8 amplifies the VHF RF signal input from the terminal 2. A UHF amplifier circuit 9 amplifies the UHF RF signal input from the terminal 3.

Reference numeral 10 denotes a double balance mixer (hereinafter, abbreviated as “DBM”) circuit, which includes a VHF oscillation signal (or UHF oscillation signal) output from the VHF amplification circuit 7 (or UHF amplification circuit 11). , And the VHF RF signal (or UHF RF signal) output from the VHF RF amplifier circuit 8 (or UHF amplifier circuit 9) is input, and the VHF RF signal (or UHF oscillation signal) causes the VHF RF signal (or , UHF RF signal) is converted to an IF signal and output. Reference numeral 11 is a UHF amplifier circuit that amplifies the UHF oscillation signal generated by the UHF oscillation circuit. Reference numeral 12 is a connection terminal between the UHF resonance circuit 19 and the UHF oscillation circuit 13. A UHF oscillation circuit 13 generates a UHF oscillation signal for converting the UHF RF signal into an IF signal. Reference numeral 14 is an amplifier circuit that amplifies the IF signal output from the DBM circuit 10, and 15 is an IF signal output terminal.

Reference numeral 16 is a VHF resonance circuit for setting the VHF oscillation signal frequency, and 17 is a VHF PLL amplification circuit for amplifying the VHF oscillation signal extracted from the VHF resonance circuit 16 and outputting it as a PLL sampling signal. is there. The oscillation signal from the VHF PLL widening circuit 17 or the UHF resonance circuit 19 is input as 18 as a PLL sampling signal, and an oscillation frequency control signal is generated based on these signals to generate the VHF resonance circuit 16 or the UHF resonance circuit. 19 is a PLL circuit that outputs an oscillation frequency control signal. Reference numeral 19 is a UHF resonance circuit for setting the UHF oscillation signal frequency.

By the way, the reason for providing the VHF PLL amplifier circuit 17 is as follows. That is, when the VHF RF signal is received, the ratio band (= maximum oscillation frequency ÷ minimum oscillation frequency) of the VHF oscillation signal generated by the VHF oscillation circuit 6 is large, and the frequency characteristic is likely to deteriorate. For this reason, the VHF oscillation signal directly extracted from the VHF resonance circuit has poor frequency characteristics, and when this is directly input to the PLL circuit 18 as a PLL sampling signal, the PLL circuit 18 may malfunction. Become. Therefore, the VHF PLL amplifier circuit 17 is required to improve the frequency characteristic of the VHF oscillation signal extracted from the VHF resonance circuit 16 and supply it to the PLL circuit 18 as a PLL sampling signal.

[0007]

[Problems to be solved by the device]

 However, in the above-mentioned conventional example, since the VHF PLL amplifier circuit is required, there is a problem that the peripheral circuit of the tuner IC becomes complicated. Further, since the oscillation signal as the PLL sampling signal is directly extracted from the resonance circuit, there is a problem that the resonance circuit is affected and the stability of oscillation of the oscillation signal is deteriorated.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, the present invention provides a tuner integrated circuit which receives a VHF band or UHF band high frequency signal, converts the high frequency signal into an intermediate frequency signal, and outputs the intermediate frequency signal. VHF oscillation signal that is input and that amplifies and outputs the VHF oscillation signal, and UHF oscillation signal that is generated by the UHF oscillation circuit that is input and that amplifies and outputs the UHF oscillation signal The circuit and the VHF oscillation signal output from the VHF amplification circuit or the UHF oscillation signal output from the UHF amplification circuit are input, and the VHF oscillation signal or the UHF oscillation signal is amplified and output as a PLL sampling signal. And a PLL amplifier circuit that operates.

[0009]

[Action]

 The above technical means act as follows. The VHF oscillation signal (or UHF oscillation signal) generated by the VHF oscillation circuit (or UHF oscillation circuit) is input to the VHF amplification circuit (or UHF amplification circuit), and the VHF amplification circuit (or UHF amplification circuit) is input. Is amplified by. The VHF oscillation signal (or UHF oscillation signal) output from the VHF amplification circuit (or UHF amplification circuit) is input to the PLL amplification circuit, appropriately amplified by the PLL amplification circuit, and output as the PLL sampling signal. ..

[0010]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows an embodiment shown in a block diagram, in which an IC is shown inside a dotted line frame and an IC peripheral circuit is shown outside the dotted line frame. FIG. 2 is a detailed circuit diagram of the PLL amplifier circuit 20 in FIG. First, the configuration and operation will be described with reference to FIG. The same blocks as those in FIG. 3 are designated by the same reference numerals and the description thereof will be omitted. 20 receives a part of the VHF oscillation signal (or UHF oscillation signal) output from the VHF amplification circuit 7 (or UHF amplification circuit 11), amplifies it, and outputs it as a PLL sampling signal. It is a PLL amplifier circuit. Reference numeral 21 is a PLL sampling signal output terminal in the IC. Reference numeral 22 is a balanced / unbalanced circuit to which the balanced PLL sampling signal output from the terminal 21 is input and which is output to the PLL circuit 18 as an unbalanced PLL sampling signal.

This embodiment is different from the conventional example shown in FIG. 3 in the following points. That is, in the conventional example, the VHF PLL amplifier circuit 17 is provided, and the VHF oscillation signal (or UHF oscillation signal) as the PLL sampling signal is directly taken out from the VHF resonance circuit 16 (or UHF resonance circuit 19). However, in this embodiment, the VHF oscillation signal (or UHF oscillation signal) as the PLL sampling signal is extracted from the VHF amplification circuit 7 (or UHF amplification circuit 11) inside the IC, and the PLL provided inside the IC is obtained. The difference is that the signal is amplified and taken out by an amplifier circuit 20 and supplied to a PLL circuit 18 by a balanced / unbalanced conversion circuit 22 provided outside the IC. As described above, the VHF PLL amplifier circuit 17 can be removed, and the PLL sampling signal is not directly taken out by the VHF resonance circuit 16 (or the UHF resonance circuit 19), which adversely affects the oscillation stability. It's gone.

Next, FIG. 2 will be described. The transistors 32 and 33 perform signal amplification, and the constant voltage power supply 38 supplies collector currents to the transistors 32 and 33. The resistors 34 to 37 are resistors for supplying a base bias voltage to the transistors 32 and 33. Transistors 39 and 40 are transistors for a constant current circuit, and flow a constant current set by a constant voltage power source 43 and resistors 41 and 42. The VHF oscillation signal (or VHF oscillation signal) input from the input terminal 31 is amplified by the transistors 32 and 33 and output from the output terminal 44 as a PLL sampling signal.

By the way, in the embodiment of FIG. 1, a VHF amplifier circuit and a UHF amplifier circuit for outputting an oscillation signal to the DBM circuit 10, a VHF amplifier circuit for outputting an oscillation signal to the PLL amplifier circuit 20, and The UHF amplifier circuit is also used, but it may be provided separately. That is, even if the VHF amplifier circuit and the UHF amplifier circuit for outputting the oscillation signal to the DBM circuit 10 and the VHF amplifier circuit and the UHF amplifier circuit for outputting the oscillation signal to the PLL amplifier circuit 20 are separately provided. I don't care.

[0014]

[Effect of the device]

 As described above, according to the present invention, the oscillation signal output from the VHF amplifier circuit (or the UHF amplifier circuit) is used, and this is input to the PLL amplifier circuit and amplified appropriately. By outputting as a PLL sampling signal, the VHF PLL amplifier circuit can be deleted from the IC peripheral circuit, and the PLL sampling signal can be extracted from the VHF amplifier circuit (or UHF amplifier circuit). Therefore, there is an effect that the oscillation stability of the oscillation circuit is not adversely affected.

[Brief description of drawings]

FIG. 1 is a block diagram of a tuner IC and its peripheral circuit according to an embodiment of the present invention.

FIG. 2 is a detailed electric circuit diagram of the PLL amplifier circuit in FIG.

FIG. 3 is a block diagram of a conventional tuner IC and its peripheral circuit.

[Explanation of symbols]

 6 VHF oscillation circuit 7 VHF amplification circuit 11 UHF amplification circuit 13 UHF oscillation circuit 17 VHF PLL amplification circuit 20 PLL amplification circuit

Claims (1)

[Scope of utility model registration request] 1. A tuner integrated circuit, to which a VHF band or UHF band high frequency signal is input, which converts the high frequency signal to an intermediate frequency signal and outputs the intermediate frequency signal, receives the VHF oscillation signal generated by the VHF oscillation circuit, A VHF amplifier circuit for amplifying and outputting the VHF oscillation signal; a UHF amplifier circuit for inputting the UHF oscillation signal generated by the UHF oscillation circuit and amplifying and outputting the UHF oscillation signal;
VHF oscillation signal output from the F amplifier circuit or the UHF
The UHF oscillation signal output from the amplifier circuit is input to
Amplifies the HF oscillation signal or the UHF oscillation signal to generate a PLL
An integrated circuit for a tuner, comprising a PLL amplifier circuit for outputting as a sampling signal.