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Патент USA US2123119

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Filed June 26, 1936
,7 "7,211
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'- mutant-5,1938")
Y iz,1z3,119
$5.31??? $113121)“; “T”? 'i V
This invention relates to a new and'improved
‘ ,appamtus used in aidinghearing and more parvvticularly to- a method and device for obtaining a
?ieted, and may be adjusted. and altered from .
‘time to time to suit. the needs of the user, as his
needs may change.
J ‘ frequency selective ampli?er for, use in aiding ‘ HThis is accomplished by providing a trans
5 ‘hearing of the partially deaf. An object of this former or electromagnetic; device, having one or 5‘
invention is to provide an- apparatus that may
v be used-in aiding hearing and which is adapted’.
tojamplify selected frequencies.
Another object of this invention is to provide
10 a hearing aid apparatus in which the frequency
more secondary windings to which are coupled devices'which select the frequencies or bands of
frequencies which aregto be attenuated. B'y al
tering or changing the characteristics of these
vlatter devices, the frequencies or bands‘ of fre- '10
response characteristic may be ‘controlled ; by ' quenciesto be attenuat?d are changed.
means of an electromagnetic device, such asa
transformer or a‘ choke coil, the frequency char-
‘it is desired to change Only One frequency-band
which is to be attenuated, this may likewise be.
acteristics of which may be'controlled or adjusted.
done with‘ equal facility.
Still another object of this. invention is to. ‘ Further'details of this invention vwarm ap- 15
provide a hearing aid apparatus with an electro- parent tqihose skilled in the art to which it
magnetic device ,which. is'adapted to controlthe
_ .
relates, from the following speci?cation and the
frequency response of said apparatusv and which
drawing, in which, brie?y, Figure 1 illustrates an ‘
is adapted to attenuate certain predetermined
embodiment ofthisinventionfFigures 2 and 2a
30 selected audio frequencies depending upon the.
hearing de?ciencies of the partially deaf ‘user.
. -
illustrateanother embodiment of this invention 20
and Figure} shows an electrical network em
A further object of this invention is to provide . ployed for the purpose of explaining the opera
'- hearing aid amplifying apparatus adap'tedto?-at-
tion of this invention. .~
- tenuate certain selected audio frequencies or
Referring to Figure‘ 1 of the drawing in detail. I
25 bands‘ of. audio frequencies depending upon» the .,reference numeral lil‘designates a sound pick-up 25
hearing de?ciencies of the hard of hearing or .1 (ital/ice» such‘as'a- micmphoner 9' Sound recm‘d
.. * partiallydeaf user.
_ j
reproducing device, and ‘the like, ‘connected to
Still a further object of this invention, is to 1 the primaryv .ll of a transformer fl! and to a
‘I providq _'a, hearing aid device’ adapted to be‘ ‘used
,byvpe'rs'qns g??cted with partial deafness, said
hearing aid device employing an electromagnetic
lapparatus having a plurality of windings, each
of said ‘windings being'adapted to function. to
/ suitable source of current supply H. The‘secl
ondary ii of vthe transformer is‘ connected to 80
.‘the‘grid electrode'ot the electric discharge device
I! and/to a C battery'lB‘ which is connected to
the cathode of the electric discharge‘ device. ‘ A
a‘ attenuatecertain frequencies or ‘bands of fre- ‘suitable'sourcejof’current supply 11 is provided
I quenciegito which thewhard of hearing" user v1s < for energizing the ‘anode of the electric discharge
‘the most sensitive.
" ' -
device amplifier 15.
Other and. further objects of this invention
The anode of the device I ;
ll-is connected to‘ the impedance winding l8
will be apparent to thoseskilled in the art to wlileh'isshunted across the output terminals l9 ‘
_ 4a which it relates ‘from the following speci?cation “of the ampli?er. ' ~'I'iie impedancé‘i? is provided 40 u
.and theclaims." '
"with two additional‘ circuits coupled to'lthe- core' r
‘ _In accordance‘iwith this‘invention _I provide a ' thereof for- the purpose of altering the frequency
; v, circuit arrangement adapted to be used in hear- characteristic of this'impedance device. These
. ,ing aid apparatus, employing an electromagnetic "additional windings are designated as 20 and 2|
‘ 45 ,device, such as a transformer, in which one or and they may be wound'xon the core 22 of the 45
_. more windings are employed to attenuate one impedance device "in various ways depending
_ or more frequenciesgor bands of frequencies the _' upon theresults desired. '{I‘hese' windings 20 and
..level of which it is desired to reduce. .
‘ ~2i may be‘ wound ‘over the winding I8 so as to
'Iy'he :apparatusof my inve tion is simple in' “be concentric‘therewith and'maybe movable with
. #0 construction and may beeasil and readily made respect to the winding ’ It in, order to vhe‘ posi- 5°
i to fulfil the needs of persons aiiiicted- with par- ‘tioned over different sections'of-the latter wind
, tial deafness. The apparatus-of myrinvention ‘_ i'ngr The-terminals of ‘the windings‘ 20 and-2|
maybe made to attenuate certain frequencies‘ are connected tojsuitable impedances 24‘ and}!
-' or bands-of frequencies, dependingupon the na-
The. .nature,.~~of these impedances
65-‘ turerof the deafness with ‘which the user is at‘, will govern the effective impedance between the 55
terminals I and 2 of the impedance II. The impedance looking into the primary winding of
power delivered to the output device connected ‘the device is
to the terminals I 9, will depend upon the effective
impedance of the device It which‘ is shunted
across said output terminals, and by properly
proportioning the various windings ll, 20. and In the above equation:
2| and connecting suitable impedances 24 and 25
zis=Ri+ Z§.+J(XI__F)=RI+
thereto, the response frequency characteristic of ' Ri=l=tesistance of primary winding.
the hearing aid apparatusof this invention can
10 be controlled as desired. Where convenient and
Ri=Resistance of secondary circuit including re
sistance component of load.
X1=Reactance of primary winding.
desirable to obtain further variation in 'the fre
quency response characteristic, an additional im ‘X:=Reactance of secondary winding.
pedance or impedancesmay be connected to the X¢=Total reactance of secondary circuit.
taps Ila and Ilb of the impedance II, or the ._
15 output circuit may be connected to these taps
In the circuit diagram shown in Figure 1 the
anode current of the electric dischargedevice.
The equation shows that for any given co
ampli?er ll obtained from the source of. cur
efficient of coupling k the impedance looking into )
rent supply I‘! passesL‘through the winding It the, primary is a function of the load impedance 20
or through this winding. and the output device connected to the secondary. -. The impedance Z1:
connected to the terminals it, This current . here corresponds to the impedance designated as
may be prevented from flowing ‘through the im
Z; in the case of the closely coupled transformer.
pedance winding II by connecting resistance
For a closely coupled transformer, Z1 is equal
across this winding between the source of current to the. quantity 1n divided by n: squared, times
supply I‘! and the anode of the device I 5 and Z2. Where m is the number of turns in the 2.5
by inserting a suitable blocking condenser be
primary of the device It and m is the number
tween this resistance and one of the terminals of turns in the secondary of this device. Z: is
of the winding II. This will prevent the anode ' the’ impedance in ohms of the impedance device
current derived from the source I‘! from. passing connected to ‘the aforesaid secondary. If Z2 is
>through the winding I I in cases where it‘ is de
a pure resistance then the effect of connecting
sired to prevent this anode
current from mag- '
netizing the core of this impedance device. '
it across the winding 1:: is in effect the same as
shunting the output device of impedance Zr with
The ‘windings II and II may be wound each a resistance. If Z: is an inductance 1-, for ex
with a different number ‘of turns or each with ample, the e?’ect of connecting it across the
a different inductance. Each of these windings winding m is the same as shunting 2;- with an. 35
may be tuned by means of suitable condensers inductance equal to the quantity m divided by
to be resonant to certain audio frequencies and m squared,‘ times n. On the other hand‘, if Z:
to absorb power at said frequencies from the is a condenser the eifect of connecting it across
circuit of the winding ll. Thus the frequency ‘the winding m is the same as shunting Zr with
characteristic of the hearing aid device may be a condenser equal to the quantity as divided by wt
varied, depending upon the characteristics of 1&1 squared, times 0, cevbeing the value of the
the impedance device. Furthermore the reso
condenser. If the transformer has more than
nance characteristics of‘the circuits of the wind
two windings the impedance looking into any
ings II and Il may be broadened if desired in winding, called for convenience the primary
one or both of these windings to cover a rela
winding, of a transformer having N windings is 45
tively broad band of frequencies, by connecting equal to the self-impedance Z, of the primary
a resistance of suitable ‘size in ‘series with each winding multiplied by the product of all the load
of these windings.
- .
impedances Zs, Zs, Zs, Zn to which the other
In Figures 2 and 2a I have shown the imped
or secondary windings are connected, and di
ance winding I. connected between the micro
vided by the sum of the products of the various 60
phone or other soimd pick-up device and a re
self impedances of the secondary windings Z2,
producing device 28, without theuse of an elec- ' ' Zs, Z4.-Za and the various load impedances with
tric discharge device ampli?er. The operation‘ which the diiferent secondary windings are not
directly associated. In Fig. 2, for instance, the
winding II or by moving thecorell, to obtain
the desired frequency response characteristic. .
The operation of the he'aringaid 'ofthis in
vention. in cases where the windings I‘, II, and
II oiithe impedance device are closely coupled
may be determined from the following when
considered with the equivalent electrical network
70 shown in Figure 3.‘
l'br the general'case of a transformer with a
mutual impedance
between primary and secondary windings the
Zilookingintothewindingllis '
the self impedance of winding ll,
Er i‘pedance
impedance ,of winding ll, Z: is‘
Marg3e5 5Essa's.‘
winding II, and Z. and
_ impedance Zs, the power loss introduced into the
circuit by the effective shunt impedance Z5 may
mally sensitive, comprising: a.v sound pick-up and _'
translating device, a vacuum tube amplifier hav- ' ‘
be determined from the following equation which ' ing an input and an output. circuit, means for
connecting, said- sound pick-up and translating
gives the power loss in decibels.
device to said ampli?er input circuit,‘ a sound re
producing “device connected to said amplifier
N- 20 log,lo(l-l—~za(zo+zr))db.
output circuit, a frequency selective attenuat- ,
If impedance Z; varies with‘frequency or if this , ing device comprising a main winding connected
impedance is fixed and either impedance Zn or
Zrvaries with frequency ‘then the response is
different at different frequencies, as may be'de
termined from the aforesaid equation.
From the foregoing it will be observed that I
have described particular. embodiments of this
15 invention in detail, however, various modi?ca
tions within the spirit and scope of this invention
across said reproducing device, said frequency
attenuating device having at least two auxiliary 10
windings coupled together, an impedance device
connected to each of said auxiliary windings for
altering the ‘frequency characteristics of said
attenuatingdevice, said impedance devices con
nected to' said auxiliary windings of said attenu
ating device being adjusted so that said attenu- »
may be made therein and I‘do not therefore
ating device will absorb power from the circuit of
desire to limit this invention to the exact details
set forth except insofar as they are de?ned by
20 the claims.
said ‘amplifier and'vfr'om said sound reproducing
device at frequencies‘ determined by the char
acteristics of said impedance devices and said 20
What I claim and desire to secure by Letters ' windings for the purpose of reducing the re
sponse ‘of the hearing aid at these predetermined
Patent of the United States is as follows:
1. A device foraiding hearing ‘by attenuat
ing frequencies to which a user of the device is
frequencies, to which the user is normally sensi
tive, to a level substantially below the normal
normally sensitive, comprising an‘input device, response of the hearing aid to the remaining fre
an output device. an electromagnetic frequency.
_ attenuating device having a winding shunted
across said output device and eletromagnetic ,
means for altering the frequency attenuating
30 characteristics of said frequency attenuating de
vice, said last mentioned means including one‘ or
more impedance circuits coupled to. said fre-,
quency attenuating device for the purpose of in
troducing losses equal to-
3. A device for aiding hearing by attenuating
frequencies to which a user of ‘the device is vnor-
‘mally sensitive, comprising: a sound pick-up and
translating device, a' vacuum tube ampli?er hav 30
ing an input circuit and ‘an output circuit, means
for connecting said sound pick-up and translating
device to said ‘amplifier input circuit, a sound‘
reproducing device connectedto said output cir
, ,
cuit, a frequency ‘attenuating device having a as,
main winding connected across said sound repro
2° ‘°g*°(‘+27<§—'f¥'z—,>)
, ducing device‘ and a pair of auxiliary windings
in decibels, where 2,; is the effective impedance , coupled to said main winding, an impedance'de
vice connected to each of said auxiliary windings,
in the circuit of said input device, Zr is the im
pedance of said output device and Z5 is the ef each of said impedance devices forming a power' 40
absorbing circuit ‘with the auxiliary winding con
fective shunt impedance of said frequency atten
nected thereto, having predetermined frequency
uating device, said losses being introduced ‘at fre
quencies determined by ‘the characteristics of characteristics such that the hearing aid device
said attenuating device for reducing the response may be adjusted to meet the deficiencies of par
‘ tially deaf persons by selecting im‘pedance‘devices
45 of the hearing aid at these predetermined, fre-'‘ of such frequency characteristics thataudio fre
quencies to which the user is normally sensitive
to a level substantially below the’ normal re .,quencies to which the partial] deaf person is
sponse of the hearing aid
the ‘remaining fre- - ‘normally sensitivewill be at enuated when the '
2. A device for aiding hearing by attenuating
frequencies to which a user of the device is'nor
selected impedance devicesareconnected‘to'said
, wILLmM norm.
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