JPS60214122A - Frequency converter - Google Patents

Abstract

PURPOSE:To reduce radiation and parasitic spurious radiation of a local oscillating frequency by forming a frequency converting circuit, a local oscillation circuit, an amplifier circuit and a frequency divider circuit on a monolithic substrate. CONSTITUTION:The frequency converting circuit 3, an IF amplifier circuit 5, the local oscillating circuit 7, the local amplifier circuit 8' and the frequency divider circuit 9 are formed on a monolithic substrate. After an output of the local oscillating circuit 7 is amplified by the amplifier circuit 8', the signal is fed respectively to the converting circuit 3 and the frequency divider circuit 9. Thus, the external radiation of the local oscillation frequency is reduced remarkably. Further, a common point between the converting circuit 3 and the amplifier circuit 5, a common point between the oscillating circuit 7 and the amplifier circuit 8' and a common point of the frequency divider circuit 9 are connected electrically and they are separated from the standpoint of layout. Thus, the parasitic spurious radiation in one monolithic chip is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a frequency conversion device, and particularly to a frequency conversion device for a television receiver.

[Prior art]

For example, as shown in FIG. 1, a conventional standard frequency conversion device for a television receiver receives a desired broadcast signal with an antenna 1, amplifies it with a high frequency amplification circuit 2, and converts it to local oscillation with a frequency conversion circuit 3. The oscillation signal of the circuit 7 and the amplifier circuit 2
directly or via an intermediate frequency amplification circuit 5t, which converts the output into an intermediate frequency signal and passes only within a predetermined band.
The intermediate frequency signal is output to the intermediate frequency output terminal 6.

In addition, Hiruzan Digital Tuning System (DTS)
), the output of the local oscillation circuit 7 is input to the frequency divider circuit 9 via the local oscillation frequency amplification circuit 8 to divide the frequency, and then input to the PLL circuit 10.
The oscillation frequency is stabilized by feeding back to the local oscillation circuit 7 a DC voltage corresponding to the difference between the internally further variably divided frequency and the internal reference oscillation frequency.

, Each of the above circuits can be integrated into a monolithic or linear integrated circuit chip (
That is, it has been found advantageous to have a plurality of active devices and associated circuitry formed simultaneously on a common substrate and interconnected (solid-state).

For example, by using this monolithic construction technology,
Compared to conventional circuit configurations using separate components and related components, many advantages are achieved in size, weight, and reliability, and the circuit configuration is relatively inexpensive.

It is difficult to integrate the frequency converter of such a television receiver into an integrated circuit, and it has not been put to practical use. DTS
Frequency divider circuit 9 and PLL for configuring the system
Although the circuit 10 is an integrated circuit, other circuits 2.
7.4.5.8 consists of individual semiconductors. The disadvantage of this conventional device is that it is necessary to distribute the output of the local oscillation circuit 7 to the frequency division circuit 9 via the frequency conversion circuit 3 and the local oscillation amplifier circuit 8, which is necessary for stable oscillation. It is necessary to provide sufficient external power. Especially since these are connected via wiring on the printed circuit board,
In order to guarantee stable oscillation and oscillation voltage level with respect to factors such as the capacitance between the package bins and the capacitance and inductance of the lead wires connecting between the package pins, the circuit configuration of the input/output section of each IC is sufficient consideration is required. For example, in the output circuit, it is necessary to set the bias current to a sufficiently large value and to minimize the distance between the ICs. Further, in order to prevent unnecessary radiation, it was necessary to take precautions such as using copper plates for the local oscillation circuit 7 and the frequency conversion circuit 3 to provide a shielding effect.

The reasons why it was previously thought that it was technically impossible to integrate the entire frequency conversion device of a television receiver into an integrated circuit were as follows: 1) In order to process signals in the 900 MHz band, fT during operation of transistors In order to maximize 3) In terms of noise figure, frequency conversion circuits and intermediate frequency amplification circuits are required to have a noise figure of 7 to 10 dB. On the other hand, frequency divider circuits do not have a noise figure design concept and require high-speed digital switching, so the same manufacturing method cannot be used. The divided frequency signal is
This is because it affects the frequency conversion circuit through the ground line and power supply line, and generates parasitic spurious signals.

However, with recent improvements in transistor manufacturing technology, it has become possible to maximize frt during operation with a low bias current (1 to 3 mA), and improvements in microfabrication technology have made it possible to increase the emitter size to 1 to 3 μm2. Furthermore, due to reductions in transistor base width resistance, manufacturing technology with high-speed switching, low noise figure, and high degree of integration has been established.

[Purpose of the invention]

The purpose of the present invention is to solve the following problems based on the above advanced manufacturing technology:
We have solved the conventional problems of local oscillation frequency radiation and the frequency divided frequency signal of the frequency divider circuit affecting the frequency conversion circuit and generating parasitic spurious, and created a frequency conversion device with stable functions. It is about providing.

[Structure of the invention]

The frequency conversion device of the present invention includes a local oscillation circuit, a two-output amplifier circuit that amplifies the output of the local oscillation circuit, and a frequency conversion circuit that converts an input high frequency signal into an intermediate frequency signal using one of the outputs of the amplifier circuit. , a frequency dividing circuit that frequency divides the other output of the amplifier circuit, and a control circuit that controls the frequency of the local oscillation circuit so that the output is locked to a predetermined frequency, and the frequency conversion circuit 1 has a local oscillation circuit. circuit, amplifier circuit.

A feature is that the frequency dividing circuits are constructed on the same monolithic board.

[Embodiment] FIG. 2 shows an embodiment of the present invention, in which the circuit within the broken line, that is, the frequency conversion circuit 3. Intermediate frequency amplifier circuit 52
Local oscillator circuit 7.1 Local oscillation frequency amplifier circuit 8'2 Frequency divider circuit 9vi-1 are fabricated on the same monolithic integrated circuit chip. The local oscillation circuit 7 inputs DC or AC signals to the local oscillation frequency amplification circuit 8', and the signals amplified by the amplification circuit 8' are input to the frequency conversion circuit 3 and the frequency division circuit 9, respectively. . As a result, compared to the conventional configuration, the local oscillation frequency is transmitted inside the Hara cage without going outside the package, which greatly reduces the radiation of the local oscillation frequency to the outside. The load on the local oscillation circuit 7 is reduced by eliminating the need to consider parasitic elements such as the capacitance existing between the pins of the package, and the capacitance and inductance of the wiring on the printed circuit board in the output section. Therefore, the power of the local oscillation circuit 7 can be reduced.

In addition, in order to prevent parasitic spurious from occurring in the frequency conversion circuit 3 due to the frequency signal divided by the frequency division circuit 9, the switching transistors in the frequency division circuit 9 are replaced by differential amplifiers. By configuring the circuit configuration in which conductive and non-conductive transistors operate symmetrically in AC terms, the influence from the power supply line and the ground line can be suppressed, and as shown in FIG.
In contrast, the pair of transistors 12 constituting the differential amplifier are structurally arranged to operate symmetrically in terms of current transformation. 7, the ground point of the local oscillation frequency amplifier circuit 8', and the ground point of the frequency divider circuit 9 are electrically connected and separated in terms of layout, thereby reducing parasitic spurious within the same monolithic chip. can be reduced.

FIG. 4 shows a layout diagram in which each circuit in FIG. 2 is constructed on the same monolithic chip. The received signal via the antenna and the high frequency amplification circuit is sent to the terminal P2 and the frequency conversion circuit 3.
In order to input the oscillation frequency of the local oscillation circuit 7 to the frequency conversion circuit 3, the terminal P14. P1
The intermediate frequency signal frequency-converted to 1.5 is output, and the output is 1.5. “The signal is input to the intermediate frequency amplification circuit 5 from the terminal P13 via the Tonami circuit 4, and the amplified signal is sent to the terminal P1.
Output to 2. On the other hand, the oscillation frequency of the local oscillation circuit 7 is determined by the circuit configuration connected to the terminals P4, P5, and P6, and the oscillation frequency is amplified by the local oscillation frequency amplification circuit 8', and its output is divided by the frequency. A signal inputted to the frequency circuit 9 and having its frequency divided is outputted to the terminal P10, and the terminals P3. P7. P16 are the frequency conversion circuits 3. The terminal P1 is a bypass terminal grounded in an AC manner through the capacitors of the local oscillation frequency amplification circuit 8' and the intermediate frequency amplification circuit 5, and the terminal P1 is a ground terminal of the frequency conversion circuit and the intermediate frequency amplification circuit. P8 is the ground terminal of the local oscillation circuit 7 and the local oscillation frequency amplification circuit 8', and terminal pH is the ground terminal of the frequency divider circuit 9.
The terminal P9 is the ground terminal of the terminal P9, and the terminal P9 is the power supply terminal.

〔Effect of the invention〕

As described above, according to the present invention, it is possible to realize economically and inexpensively a frequency conversion device that does not cause unnecessary radiation of the local oscillation frequency, does not generate parasitic spurious, and has excellent frequency characteristics.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing a conventional example, Fig. 2 is a block diagram showing an embodiment of the present invention, Fig. 3 is a layout diagram of the frequency dividing circuit in Fig. 2, and Fig. 4 is a block diagram showing an embodiment of the present invention. It is a layout diagram showing an example of layout. 1... Antenna, 2... High frequency amplification circuit, 3... Frequency conversion circuit, 4... Filter circuit, 5... Front intermediate frequency amplification circuit, 6.
...Intermediate frequency output terminal, 7...Local oscillation circuit, 8.8', 12...Local oscillation amplifier circuit,
9...Frequency divider circuit, 10...PL
L circuit. Kyu 4 kyou

Claims (1)

[Claims] a local oscillation circuit, a two-output amplifier circuit that amplifies the output, and a frequency conversion circuit that converts an input high frequency signal into an intermediate frequency signal using one of the outputs of the amplifier circuit;
The frequency conversion circuit 1 has a frequency dividing circuit that divides the frequency of the other output of the amplifier circuit, and a control circuit that controls the frequency of the local oscillation circuit so that the output is locked to a predetermined frequency. A frequency conversion device characterized in that an amplifier circuit and a divide-by-2 circuit are constructed on the same monolithic board.