JPH0639685Y2 - Ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an ultrasonic diagnostic apparatus having a TV monitor.

(B) Conventional technology and its problems Conventionally, in this type of apparatus, an echo signal obtained by radiating ultrasonic waves to a subject is amplified by an echo amplifier, and then the echo signal is displayed as a diagnostic image on a TV monitor. There is something like this. The above echo amplifier amplifies a weak high frequency echo signal. Therefore, if a TV monitor is mounted close to this echo amplifier, the switching generated when the output transistor of the deflection output circuit of the TV monitor operates. There is a problem that noise is mixed in the echo signal and the image quality is deteriorated. That is, as shown in FIG. 3, when a pulse is applied between the base and emitter of the output transistor of the horizontal output circuit ((a) in the same figure), a sawtooth wave is generated in the deflection coil and the output transistor is output during the blanking period. A flyback pulse is generated in the collector of (Fig. 3 (b)). Since this flyback pulse includes ringing, it mixes with the echo signal and becomes noise (FIG. 7C).

Conventionally, as a countermeasure against this, the TV monitor is separated from the echo amplifier, or the entire TV monitor or the high voltage generation circuit is shielded. However, such measures have a problem that it is not possible to sufficiently cope with the downsizing and weight reduction of the device.

The present invention has been made in view of such circumstances, and it is possible to effectively reduce the influence of switching noise of a TV monitor while maintaining the characteristics of the device and without making a large circuit change. The purpose is to do so.

(C) Means for Solving the Problems In order to achieve the above-mentioned object, the present invention provides a horizontal output circuit having an output transistor, a deflection coil, a damper diode and a resonance capacitor. In an ultrasonic diagnostic apparatus having a TV monitor to which a high voltage generation circuit having a flyback transformer for boosting a back pulse is connected, ferrite beads are inserted between the output transistor and the flyback transformer.

(D) Function In the ultrasonic diagnostic equipment of the present invention, if a ferrite bead is inserted between the output transistor and the flyback transformer, the high frequency loss of the ferrite bead supplies the flyback transformer from the output transistor of the horizontal output circuit of the TV monitor. Ringing of the generated flyback pulse is suppressed. Moreover, since the ferrite beads act only on the high frequency signal, they do not interfere with the circuit operation.

(E) Embodiment FIG. 1 is a circuit configuration diagram of a horizontal output circuit and a high voltage generation circuit of a TV monitor of an ultrasonic diagnostic apparatus according to an embodiment of the present invention.

In the figure, reference numeral 1 is a horizontal output circuit built in a TV monitor of an ultrasonic diagnostic apparatus, 2 is a high voltage generation circuit, 4 is an output transistor for switching the horizontal output circuit 2, 6 is a deflection coil, and 8 is this deflection. A capacitor for waveform distortion correction connected to the coil 6, 10 is a damper diode, and 12 is a resonance capacitor. And the resonance capacitor
Ferrite beads 14 are inserted in series with 12.

Reference numeral 16 is a flyback transformer that boosts the flyback pulse output from the horizontal output circuit 1, 18 is a rectifying diode, and 20 is a smoothing capacitor. Reference numeral 22 is a coupling capacitor.

Next, the operation of this embodiment will be described with reference to the waveform chart shown in FIG.

When a 15.75 KHz pulse is applied from the input terminal 24 of the horizontal output circuit 1 to the base of the output transistor 4 (Fig. 2 (a)), a periodic sawtooth wave current is generated in the deflection coil 6 (Fig. 2 (b)). )), A flyback pulse is generated in the collector of the output transistor 4 during the retrace period of the sawtooth wave ((c) in the figure). This flyback pulse is supplied to the primary coil of the flyback transformer 16 of the high voltage generation circuit 2. As a result, the flyback pulse voltage is boosted and a high voltage is generated in the secondary coil of the flyback transformer 16. Then, this voltage is applied to the anode of the picture tube not shown.

In the circuit of this embodiment, since the ferrite beads 14 are inserted between the output transistor 4 and the flyback transformer 16, the high frequency loss of the ferrite beads 14 suppresses the ringing of the flyback pulse. As a result, even if a TV monitor is mounted close to the echo amplifier, noise will not be mixed in the echo signal (FIG. 9 (d)). Moreover, the ferrite beads 14 are
Since it acts only on high frequency signals, it does not interfere with the circuit operation.

(F) Effect As described above, according to the present invention, it is possible to effectively reduce the influence of switching noise of the TV monitor while maintaining the characteristics of the device and without making a large circuit change. Therefore, excellent effects such as being able to sufficiently cope with downsizing and weight saving of the device are exhibited.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram of a horizontal output circuit and a high voltage generation circuit of a TV monitor of an ultrasonic diagnostic apparatus according to an embodiment of the present invention, FIG. 2 is a waveform diagram of a signal generated in this circuit, and FIG. TV
It is a wave form diagram of the signal generated in the circuit of the monitor. 1 ... Horizontal output circuit, 2 ... High voltage generating circuit, 4 ... Output transistor, 6 ... Deflection coil, 10 ... Damper diode, 12
… Resonance capacitor, 16… Flyback transformer.

Claims (1)

[Scope of utility model registration request] 1. A TV in which a high voltage generating circuit having a flyback transformer for boosting a flyback pulse from the horizontal output circuit is connected to a horizontal output circuit having an output transistor, a deflection coil, a damper diode and a resonance capacitor. An ultrasonic diagnostic apparatus having a monitor, wherein ferrite beads are inserted between the output transistor and the flyback transformer.