High power klystron tuning mechanism having means for detecting non-synchronous tuning channel conditions

A high power klystron turning mechanism identifies which tuning channel has been set. A plurality of tuners are inserted into individually associated cavity resonators. A tuner supporting mechanism includes a plurality of screws which protrude to force the tuners predetermined distances into the cavity resonators. A detector detects the position of the tuner support mechanism, and therefore how far the protruding screw structure has forced a tuner into the cavity resonators, which, in turn, indicates the tuning. The detector comprises a preset plate which selectively operates a plurality of switches at locations corresponding to the protruded screws and at another location in order to generate a more accurate tuning identification. The detector may be either a light-photo cell combination or mechanical switches.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention relates to a klystron tuning mechanism, and more 
specifically to a high power klystron tuning mechanism for altering the 
high frequency power. 
2. Description of the Prior Art 
A high power klystron includes an electron gun for releasing electrons 
therefrom and thereby forming an electron beam, a RF section for 
interaction between the electron beam and the high frequency power, a 
collector for collecting the electrons, and a focusing unit for focusing 
the electron beam. The RF section includes cavity resonators, tuners for 
varying resonance frequencies of the cavity resonators, respectively, and 
a tuning mechanism for connecting and supporting the tuners. In case the 
high frequency power to be amplified is desired to be varied, it is 
necessary in the high power klystron to adjust a plurality of resonance 
frequencies of the cavity resonators to proper ones while observing 
frequency characteristics thereof on all such occasions. This causes 
inconvenience in its handling and operation as, compared with a travelling 
tube which is to amplify microwaves like the foregoing high power 
klystron. 
To eliminate such inconvenience in the operation there is available a high 
power klystron including a tuning function which possesses a preset 
function in which it becomes possible at a previously set specific 
frequency to obtain easily a predetermined band width by carrying out only 
channel switching operation without performing any additional adjustment 
work. A prior art high power klystron including such a preset function as 
described above is arranged as illustrated in FIG. 1 for example. More 
specifically, the RF section of the high power klystron comprises a 
plurality of cavity resonators 1, tuners 2 of the same number as that of 
the cavity resonators wherein the cavity resonators 1 are varied in their 
volumes to change their resonance frequencies, and bellows 3 connected to 
the tuners 2 and the cavity resonators 1, respectively, for enabling the 
tuners 2 to go into and out (slide) the cavity resonators 1 by their 
mechanical deformation while keeping a vacuum in the high power klystron. 
A tuning mechanism 4, which is connected to the tuners 2 each serving as 
described above to alter the resonance frequencies of the cavity 
resonators 1, comprises a tuner supporting mechanism 5 for exerting on the 
tuners 2 a biasing force in the opposite direction to the side of a vacuum 
tube of the high power klystron along the shafts of the tuners 2 at all 
times with the aid of restoring force of springs 8, a preset part 7 
including means for moving parts on a preset plate 10 in parallel in 
response to a rotation of a pinion 11, the preset plate 10 being fixedly 
mounted on the RF section through the supporters 6 and allowing a 
plurality of sets of frequency setting screws 9 to be attached thereto, a 
tuning channel detector part 25 (refer to FIG. 2B) for detecting the fact 
that which frequency setting screw 9 is connected to the tuner 2, and a 
driving mechanism 13 for rendering a connection or a disconnection between 
the frequency setting screw 9 and the tuner shaft 12. 
Herein, designated at 14 are bearings, 15 is a fixed plate, 16 is a locking 
shaft, 17 is a movable plate, 18 is a unlocking plate, 19 is a frequency 
alteration shaft, and 20 are locking plates. 
Referring to FIGS. 2A and 2B, the tuning channel detector part 25 is 
illustrated in detail. In the lower part of the preset plate, 10, slits 21 
are provided at locations corresponding to the frequency setting screws 9 
(FIG. 2A). In order to permit the transmission of light through these 
slits 21, four successive photointerrupters 22 (each photointerrupter 22 
comprises a light emitting diode 23 and a photodiode 24 as seen in FIG. 
2B) are mounted on the preset plate 10 at the same pitch or interval as in 
the frequency setting screws 9. The photodiode 24 becomes conductive as 
light emanating from the light emitting diode 23 of the photointerrupter 
22 reaches the photodiode 24 after passage through the slit 21, whilst the 
same photodiode 24 becomes non-conductive as the same light is 
interrupted. The slits 21 are disposed such that signals detected by the 
tuning channel detector part 25 are as listed in TABLE 1 for respective 
channels with the assumption of the conductive and non-conductive states 
of the photodiode 24 set to be 1 and 0. 
TABLE 1 
______________________________________ 
Tuning Signals Detected by Tuning 
Channels Channel Detector Part 
______________________________________ 
1 1 0 1 1 
2 0 1 1 0 
3 1 1 0 1 
4 1 0 1 0 
5 0 1 0 0 
6 1 0 0 0 
______________________________________ 
More specifically, with the arrangement illustrated in FIG. 2A (in the case 
of the tuning channel 1 in TABLE 1) a signal of 1011 is generated, and 
likewise once another frequency setting screw 9 is connected with the 
tuner 2 constituting part of the cavity resonator 1 by moving the preset 
plate 10, a signal corresponding to an associated tuning channel is 
generated from the tuning channel detector part 25. On the basis of the 
detected signal, it becomes possible to judge the fact that the associated 
klystron is set to which tuning channel. 
A preset operation in the tuning mechanism, in which operation a 
predetermined band width is previously set for one tuning channel of the 
high power klystron through a set of the frequency setting screws 9 
disposed along a drift tube of the cavity resonator, is performed as 
follows: First, an adjustment is performed with the aid of the frequency 
setting screws 9 such that the band width of the predetermined channel is 
yielded in the state of FIG. 1. In succession, the locking shaft 16 fixed 
through the bearing 14 to the fixing plate 15. The shaft is turned until 
the movable plate 17 makes contact with the unlocking plate 18. At this 
time, contacts between the tuner shafts 12 connected to the tuners 2 
become disconnected. In this state, the frequency alteration shaft 19 is 
rotated to bring another frequency setting screw 9 into coincidence with 
the central axis of the timer shaft 12. At this location, the movable 
plate 17 is again moved until the movable plate strikes the locking plate 
20 through the locking shaft 12. In this state, the degree of a projecting 
length of the frequency setting screw 9 is adjusted such that a 
predetermined band width characteristic is ensured in another tuning 
channel which is different from the foregoing tuning channel. With 
repetition of such adjustment a plurality of tuning channels of the high 
power klystron can be set previously. 
In the tuning mechanism described above, any tuning channel is specified by 
a plurality of the slits 21 as illustrated in FIG. 2A, so that it is 
impossible to quickly and completely make the slits 21 and the 
photointerrupters 22 coincident with each other positionally, resulting in 
a difficulty of generated signals being slightly shifted in time. 
Accordingly, there might sometimes occur an inconvenience that upon 
alteration of a tuning channel, a signal of another tuning channel is sent 
from the tuning channel detector part. More specifically, an error might 
be produced in the signals detected by the tuning channel detection part 
listed in TABLE 1 that signals of other tuning channels are detected among 
the respective channels as listed in TABLE 2. Namely, there might be 
produced a possibility that erroneous detected signals with a pattern of 
TABLE 2 (signals indicated in parentheses) are issued. 
TABLE 2 
______________________________________ 
Tuning Signals Detected by Tuning Channel Detector 
Channels Part 
______________________________________ 
6,4 1000 (0011, 1001, 0010, 0001), 1010 
1 1011 
6,5,4 1000 (00011, 1001, 0010, 0001), 0100, 1010 
2 0110 
6,5 1000, (0010), 1000 
3 1101 
6,5 1000, (0010), 0100 
4 1010 
6 1000, (0010) 
5 0100 
6 1000 
______________________________________ 
Channel alteration is thus recognized to have been completed at an 
incorrect location upon the alteration of a tuning channel, which impedes 
alteration to a tuning channel to be used. 
SUMMARY OF THE INVENTION 
To solve the problems with the prior art, it is an object of the present 
invention to provide a high power klystron tuning mechanism in which a 
correct judgment on a tuning channel can securely be performed. 
To achieve the above object, there is provided in a first aspect of the 
present invention a high power klystron tuning mechanism, said tuning 
mechanism comprising: a plurality of cavity resonators constituting 
together part of a vacuum tube of a high power klystron and each disposed 
at a predetermined pitch.; a plurality of tuners each adapted to be 
insertable into the-cavity resonators; a tuner supporting mechanism 
connected with the tuners for excerting a force on the tuners at all times 
in the opposite direction to the side of the vacuum tube; a preset plate 
making contact with at least part of the tuner supporting mechanism and 
serving to integrally support a plurality of protruded structures each of 
which forces the tuners into the cavity resonators at the same pitch as 
that of the cavity resonators; a driving mechanism including means for 
making a connection or a disconnection between each of the protruded 
structures of the preset plate and each of the tuners corresponding to the 
protruded structures; and a detector part for detecting which protruded 
structure among the plurality of the protruded structures of the preset 
plate is connected with a tuner corresponding thereto, wherein part of 
each the protruded structure is previously set to protrude through the 
driving mechanism and the preset plate is driven to slide intermittently 
at the same pitch as the pitch of arrangement of the cavity resonators in 
the direction of the arrangement of the cavity resonators whereby the 
tuners are inserted into the cavity resonators in conformity with a 
previously set tuning channel pattern, the improvement being such that the 
detector part comprises: a part to be detected possessing gaps such as 
slits and holes formed in part of .the preset plate so as to correspond to 
the previously set protruded structures; a plurality of switches, almost 
all thereof fixedly mounted at locations corresponding to the protruded 
structures and part thereof fixedly mounted at locations shifted from the 
corresponding locations of the protruded structures, for detecting 
locations of the gaps formed in the part to be detected; and detector 
means for detecting which tuning channel among the previously set tuning 
channels has been set, on the basis of signals detected by the switches. 
Further, there is provided in a second aspect of the present invention a 
high power klystron tuning mechanism as set forth in the foregoing first 
aspect, wherein there is disposed at least one opening part at locations 
not in synchronism with the respective locations of the respective 
protruded structures of the preset plate and at locations where the 
switches are operable. 
There is further provided a high power klystron tuning mechanism as set 
forth in any one of the foregoing aspects, wherein each of the switches is 
a photointerrupter composed of a light emitting diode and a photodiode. 
There is still further provided a high power klystron as set forth in any 
one of the foregoing aspects, wherein all of the plurality of the switches 
are contact type switches. 
There is still yet further provided a high power klystron tuning mechanism 
as .set forth in any one of the foregoing aspects, wherein the switches 
fixedly mounted at the locations corresponding to the gaps formed in the 
part to be detected among the plurality of the switches are 
photointerrupters, each photointerrupter being composed of a light 
emitting diode and a photodiode, and wherein the switches fixedly mounted 
at locations not corresponding to the gaps are contact type switches. 
In accordance with the present invention, the gaps such as slits and holes 
are formed at locations corresponding to the protruded structures which 
were previously set in part of the preset plate, and almost all switches 
for detecting the gaps are fixedly mounted at the locations corresponding 
to the protruded structures while the other switches are fixedly mounted 
at the locations shifted from the locations corresponding to the protruded 
structures. The identity of the tuned channel is detected on the basis of 
output signals from the detector switches. This improves detection 
accuracy of the tuning channel. 
Further, in accordance with the present invention the opening part is 
disposed at the location not in synchronism with the frequency setting 
screw whereby a mistaken tuning channel is prevented from being set upon 
any tuning channel being altered. 
The above and many other advantages, features and additional objects of the 
present invention will become manifest to those versed in the prior art 
upon making reference to the following detailed description and 
accompanying drawings in which preferred structural embodiments 
incorporating the principles of the present invention are shown by way of 
illustrative example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
In what follows, there will be described the present invention further in 
detail in association with some preferred embodiments illustrated the 
attached drawings (FIGS. 3A through 7B). 
Referring to FIGS. 3A and 3B, a construction is illustrated of a portion of 
a klystron tuning mechanism according to the first embodiment of the 
present invention. For elimination of overlapping, like symbols shall be 
applied to like portions as those of the prior art cases (FIGS. 2A and 
2B), and the description thereof will be omitted and only different 
portions will be described in detail (to the other embodiments the same 
shall also be applied). 
In a klystron tuning mechanism illustrated in FIGS, 3A and 3B, two slits 
51, 51 are formed in the lower part of a preset plate 10. Three successive 
photointerrupters 52a are fixedly mounted on the left end of the preset 
plate 10 and a photointerrupter 52a is fixedly mounted at an intermediate 
location between tuning channels 3 and 4, i.e., not corresponding to any 
channel; please see TABLE 3 for a better understanding thereof. 
Referring to TABLE 3, there are listed detected signals in the respective 
tuning channels with the construction of the embodiment described above. 
TABLE 3 
______________________________________ 
Tuning Channel Detection Signals 
______________________________________ 
1 0 0 1 0 
2 0 1 0 0 
3 1 0 0 0 
(0.sup. 
0 0 .sup. 1) 
4 0 0 1 1 
(0.sup. 
0 0 .sup. 1) 
5 0 1 0 1 
(0.sup. 
0 0 .sup. 1) 
6 1 0 0 1 
______________________________________ 
In such a manner, in the present embodiment no other channel is formed 
between tuning channel to be altered, and hence erroneous detection can be 
avoided. 
Referring to FIGS. 4A and 4B, there is illustrated the construction of a 
portion of a klystron tuning mechanism according to the second embodiment 
of the present invention. In the present embodiment a contact type switch 
26 is usable instead of the photointerrupters 52a of FIGS. 3A-3B in the 
first embodiment. Hereby, the tuning mechanism can advantageously be 
constructed only with a mechanical mechanism. 
Referring to FIGS. 5A and 5B, there is illustrated the construction of a 
portion of a klystron tuning mechanism according to the third embodiment 
of the present invention. The present embodiment is of a combination of 
the first and second embodiments in which three successive 
photointerrupters 52b (see FIG. 5A) are disposed at the left of the preset 
plate 10 and a contact type switch 26 is disposed at a location where it 
becomes conductive between tuning channels 3 and 4. 
Referring to FIGS. 6A and 6B, there is illustrated in the forms of front 
and side views a portion including a preset plate 10, a pinion 11, a 
frequency setting screw 9, and a tuning channel detector part 25 of the 
high power klystron tuning mechanism according to the fourth embodiment of 
the present invention. There are provided two slits 51 at locations 
corresponding to those of the frequency setting screws 9 on the lower part 
of the preset plate 10 which supports the frequency setting screw 9 being 
a plurality of protruded structures connected with the tuners constituting 
part of the high power klystron cavity resonators. Additionally, wider 
opening parts. 27a and 27b (FIG. 6A) are provided such that one or two 
photointerrupters 52c becomes or become conductive between tuning 
channels. Four successive photointerrupters 52c are fixedly mounted in the 
same interval as in the frequency setting screws 9 corresponding to the 
slit 51 (FIG. 6A) for permission of light transmission. 
TABLE 4 lists signals through the respective tuning channel with the 
assumption of conductive and non-conductive states to be 1 and 0. 
TABLE 4 
______________________________________ 
Tuning Signals Detected by Tuning Channel Detector 
Channel Part 
______________________________________ 
1 1101 (1100 or 1000) 
2 1010 (1000 or 0000 or 0001) 
3 0101 (0001 or 0011) 
4 1011 (0011 or 0110) 
5 0111 (0110 or 1100) 
6 1110 (1100) 
______________________________________ 
Referring to FIGS. 7A and 7B there are illustrated the fifth embodiment of 
the present invention in the forms of sectional and side views. The preset 
plate 10 has its