close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2133808

код для вставки
Oct“ 18, 1938,
w_ L. CARLSQN
'
2,133,808
RADIO RECEIVER
Filed Sept. 27, 1933
2\Sheets—Sheet l
(
'
n:
15
111
=:|
m i
“H.
|
2
\'“
Wm“
J '
INVE'NTOR
WendqllL . Cdrlqon
j
"
act. 18, 1938.
" w_
CARLSQN __
RADIO
'
RECEIVER
'
Filed Sept. 27, 1933
OFCIRCUIT
'
I
2 Sheets-Sheet 2
NORMAL sELEcT/v/TY
0F‘ c/Rcu/Ts A ?ND A’
COMBINED
SELECT/wry
2,133,808
SELECT! v1 7' v
OF
CIRCUIT H For? SIDE
BAND RECEPTION
,
A’ UNCHANGED FOR 6105
BAND RECEPTION
15.?
2
E
Q’
COMB/NED SELECT/V17)’
OF CIRCUITS A AND/7'
F'Ol? SIDE .BHND
RECEPTION
155
FREQUENCY
SIDE BEND
SIDE BAND
CARRIER
NORMAL SELECT/WT)’
' R [14.9
OF’ B AND C CIRCUITS
/"~\
SELEC'T/V/TY
.
"151“_
0F 9.,q.v.c.
C’RCUIT
‘
>
-
,
'
1
\
SELECTIV/TY OF
C CIRCUIT FOR
159
SIDE BHND
HE¢EPTION
SELECTIV/TY 0F‘
Bc/Rcu/r FOR
SIDE BAND
3
RECEPTION
igi
=1:
(‘J
FREQUENCY
‘
_
'
‘—v—’ T SIDED/1ND
‘_-v—’
SIDE BEND
-
CARRIER
165
i
\
1t
{D
FREQUENCY
_
'
BY
INVENTOR
WendelLL. Carlson
g!
'
2,133,808
Patented Oct. 18, 1938
~ UNITED STATES PATENT‘ MEI-cs3?’
RADIO RECEIVER
Wendell L. Carlson, Haddon?eld, N. J.,'assignor'
to Radio Corporation of America, a corporation
of Delaware
Application September 27, 1933, Serial’No. 691,120
16 Claims‘. (01. 250-20) '
My invention relates to radio receivers and par
ticularly to a receiver designed to be operated
either-as a conventional highly selective receiver
or as a high ?delity receiver designed to suppress
ea part of one side band of the incoming signal.
The usual broadcast transmitter transmits .a
signal which consists of a carrier wave and the
upper and lower side bands. .The- conventional
receiver is tuned to the carrier wave frequency
10 so that equal amounts of the two side bands are
received. With a crowded broadcast band such
a receiver generally must be so sharply tuned
trol circuit'j permits the-receiver to operate. In
other words, the receiver must bev tuned to one
side of the middle of the main channel.
drawings, in
which"
.
I
,_
Figure 1 is a circuit diagram of a receiver-con
structed' in accordance with oneembodiment of
my
invention;v
»
'
,
,
'
,.
characteristics of certain tuned circuits of the
receiver shown in Fig. 1; and
reproduced voice or music from a received
modulated carrier wave is impaired.
istics of the receiver shown in Fig. 1. _ 1:
permits interference from stations on adjacent
channels.
It is, accordingly, an object of my invention to
5-25 provide an‘improved receiver which may be op
erated selectively either as a conventional re
ceiver or as a high ?delity receiver.
It is a further object of my invention to pro
vide a high ?delity receiver that shall have com
paratively high gain and improved selectivity.
It is a still further object of my invention to
provide an improved receiver for receiving main
ly the carrier and one side band of a radio
signal wave.
In practicing my invention, and in a preferred
embodiment thereof, I provide a superheterodyne
receiver with a control circuit which is. sharply
tuned to the intermediate frequency for the pur
pose of making the receiver inoperative until it
is tuned exactly to the carrier frequency of the
desired station. Operated in this manner, the
receiver is sharply selective. I further provide
switching means for broadening the tuning of
certain circuits on one side of the carrier fre
quency only, whereby the receiver may be op
erated as a less sharply selective, high ?delity
receiver. The tuning is broadened. su?iciently
to permit the passage of one complete side band.
The other side band, except the lower frequency
.50 end thereof, is appreciably attenuated or sup
pressed.
‘
»
' . Figs. 2 and 3 are curves showing the selectivity
that the high frequency components of the side
bands are cut off, whereby the quality of the
The cutting off of the side bands may be
avoided by merelybroadening the tuning of the
receiver circuits, but this is objectionable for two
reasons. In the ?rst place, it greatly lowers the
gain of the receiver, and in the second place, it
'
Other features and advantages of my inven
tion will appear from the following description v5,
taken in- connection with the accompanying
, _- I 1
Fig. 4 shows certain signal output character
a
,
vReferring to the embodiment, of my invention
shown in Fig. 1,.itcomprises a superheterodyne
‘receiver. which includes a radio frequency am:
pli?er tube vI, a ?rst detector tube 3, an in
termediate frequency ampli?er tube 5,v and a sec 20
ond detector .tube 1. These ampli?er and de
tector tubes may be vany suitable type of space
discharge device. In. the example illustrated,
they are conventional screen grid and three ele
ment tubes.
. .
,
,25
The ampli?er tube l is provided with an input
circuit which includes a radio frequency trans
fo-rmer' 9 having a primary winding H and a
secondary winding I3, the primary winding ll
being connected toan antenna l5 and to ground. ,
In order .to make the winding 13 tunable at "
radio frequencies, it is shunted by a variable
tuning condenser H, a blocking condenser l9, and
a ?xed tuning j.condenser 2|, all connected in
‘series. This vtunable circuit will be referred to _,
as the'selecting or ‘?lter circuit A. The ?xed
tuning. condenser 2| is provided with a short
circuiting switch 23 for changing the tuning
of the selecting circuit A when the receiver is to
be adjusted for single side band reception. The 40
control grid of the ampli?er tube l is provided
with av constant negative bias by means of a grid
biasing resistor 25 connected in the cathode-lead
and shunted by a radio frequency bypass icon
denser 21. It is also provided with a variable
biasing or controlling potential as hereinafter
described.
.
,
>
The'ampli?er tube l is provided with an output
circuit which is coupled to the input circuit of
the detector tube 3 through a transformery29. ,
The secondary 3| of the transformer 29 is shunted
by a variable tuning. condenser '33 and a blocking
It is evident that the receiver, when operat
ing as a single side band, high ?delity receiver
must always be tuned to a single side band of an
radio frequency ?lter circuit A’. The condensers
incoming signal before the above-mentionedcon
l1 and _33-are units of, a gang condenser ‘which ‘
condenser 35 connected in series to form a second
2
2,133,808
are operated by a common control as indicated
by the dotted line 31.
When the receiver is operated as a conven
tional, sharply selective receiver, the condenser 2|
is short-circuited and the tuned circuits A and
A’ are tuned to the same frequency. When oper
ated as a high ?delity receiver, the switch 23 is
open and the circuit A is tuned to a slightly
higher frequency than the circuit A’.
"
tector ‘I is supplied to a suitable audio frequency
ampli?er or translating device (not shown)
through an audio frequency transformer 19.
The above described superheterodyne receiver
is provided with an automatic volume control or
A. V. C. circuit which includes an intermediate
gequency ampli?er tube 8| and a recti?er tube
In the particular embodiment shown, the am
The superheterodyne oscillator 39, which is pli?er tube 8| is of the screen grid type having a
coupled as indicated, to the ?rst detector 3 for _. control grid which is maintained at the desired
producing the intermediate frequency signal, negative potential through a biasing resistor 85
may be of any suitable type. It includes a tuning in the cathode lead.
condenser 4| which is operated as indicated, by . The input circuit of the ampli?er 8| is coupled
to the output circuit of the band pass ?lter B
15 the above-mentioned common control for set
ting the oscillator at a frequency above that to by means of a coupling condenser 81 and grid
which the radio frequency circuits are tuned by impedance 88.
The ampli?er tube 8| is provided with an out
an amount equal to the intermediate frequency}
The detector tube 3 is provided with an output ‘ put circuit which is coupled to the input cir
20 circuit which is coupled to the input circuit of cuit of the recti?er tube 83 through a three wind
the intermediate frequency ampli?er tube 5 ingtransformer 89. The primary winding 9| of
the transformer ‘89 is tuned to the intermediate
through a transformer 43.
The primary winding 45 and, the secondary frequency'by means of a condenser 93. The
winding 41 of the transformer 43 are tuned by secondary winding 95 is in the recti?er circuit
andlis closely coupled to the primary winding 9|
25 means of condensers 49 and 5|, respectively, to
10
form a band pass ?lter B of the type commonly
employed in superheterodyne receivers. The tun
ing condenser 49 is connected in series with a
second tuning condenser 53 which is provided with
30 a short circuiting switch 55. When the switch
55 is closed, the band pass range of the ?lter B
is madewider and shifted to a slightly lower fre
quency.
The control grid 56 and the cathode 58 of the
intermediate frequency ampli?er tube 5 are con
nected to the tuned secondary circuit of the ?lter
B. - The connection of the cathode 58 to this cir
cuit is made through automatic volume control
circuits which will be described hereinafter.
The control grids of both the ?rst detector
tube 3 and the intermediate frequency tube 5 are
supplied with the proper constant bias by means
of resistors 51 and 59 in the cathode leads, these
resistors being shunted by radio frequency by
45 pass condensers BI and 83, respectively.
The output of the ampli?er tube 5 is fed to
the input circuit of the second detector tube 1
through a radio frequency transformer 65 hav
ing a primary winding 61 and a secondary wind
50 ing 69. Tuning condensers: ‘H and 13 are con
nected across the windings 61 and 69, respectively,
to form a band pass ?lter 0 having a predeter
mined selectivity characteristic.
In order to broaden the tuning of the ?lter
C for high ?delity reception, a coupling coil ‘I5
is connected in series with the secondary winding
69 and coupled as indicated,vto the primary wind
ing 61. A switch 11 is provided for connecting
the tuning condenser 13 across or in parallel with
60 either the secondary winding 89 itself, or the
secondary winding 89 and the winding 15 in
series. By throwing the switch ‘IT to the position
shown to connect condenser 13 across both wind
ings, the tuning of the ?lter C is broadened to
avoid the cutting off of the carrier wave side
bands. This broadening of the tuningis caused
by the increase in coupling between the primary
and secondary circuits, as explained in my
Patent No. 1,871,405. The amount of inductance
70 in coil 15 and the degree of coupling to primary 61
are adjusted so as to obtain the desired fre
quency range with the same increase of fre
quency range on each side of resonance com
pared to the sharp resonant circuit.
The audio frequency output of the second de
10
15
20
25
to broaden the frequency range of the trans
former.
.
'
.
The input circuit of the recti?er tube 83 in
cludes a resistor 91 and a source of biasing poten
tial such as a biasing battery 99, connected in 30
series‘ with the secondary winding 95 and the
resistor 91.: 'When intermediate frequency signal
energy isfed to recti?er 83, a voltage drop having
a value depending upon the strength of an in
coming signal will appear across resistor 91. The 135
voltage drop across the entire resistor 91 is ap
plied to the control grids of ampli?er tube | and
detector tube 3 through a conductor NH and
?lter resistors Hi3 and I95. A ?lter condenser
I01 connected between the end of the resistor 91
and ground prevents audio frequency signals
from appearing in the output of the volume con
trol circuit in accordance with well known prac
tice.
'
'
'
The voltage drop across aportion of the resistor -
91 is applied to the control'grid 56 of the inter
mediate frequency ampli?err tube 5 through a
conductor I09. This portion of the resistor is
shunted by another ?lter condenser Ill.
The biasing battery 99 prevents the A. V. C. 60
circuit from becoming effective to reduce the gain
of .the receiver until after the strength of the
incoming signal exceeds a predetermined value,
since the anode of recti?er 83 is maintained nega
tive until the signal voltage across the secondary
95 exceeds said value.
In accordance with my invention, the receiver
is also provided with a highly selective circuit
tuned to the intermediate frequency for main
taining the receiver in an inoperative condition 60
except at the times that the said highly selective
circuit is passing energy; This circuit, which
may be referred to as the quiet automatic volume
control or Q. A. V. C.,circuit, includes an inter
mediate frequency ampli?er tube ||3, a recti?er 65
tube I I5 and a control tube H1.
The intermediate‘ frequency ampli?er tube ||3,
which is of thescreen grid type in the example
illustrated, has its input electrodes coupled to the
output circuit of the preceding ampli?er tube -8|
by means of the other secondary winding H9 of
the intermediate frequency transformer 89, the
secondary winding “9 being loosely coupled and
sharply tuned to the intermediate frequency by
vmeans of a condenser |2|.> The intermediate
in ’
2,133,808
frequency ampli?er H3 is provided with an output circuit coupled to the inputcircuit of the rec
ti?er tube I I 5 through an intermediate frequency
transformer I 23. The transformer I 23is‘sharp
ly tuned to the intermediate frequency ‘by means
of condensers I25 and I21.
3
the Q. A. V. C. circuit‘is tuned to the middle of
the “pass” range of the ?lters B and .C'.
‘
'
With the switches thrown to the positions
shown in Fig. 1 for high ?delity reception, the
resonance curve of circuit A is shifted to ahigher
.
frequency as ‘shown vby the curve I53 in Fig. 2.,
The control tube II‘! is of the three-electrode “the resonance curve I55 of circuit A’ remaining
type having a cathode I29, a control grid I3I, and unchanged. The combined selectivity of circuits
an anode I33. The cathode I29 is connected A and A’ is represented by the curve I57; I
10 through a conductor I35 to the cathode end of the
Also, as shown by the curve I59 in Fig. 3, the 1' '
biasing resistor 59 of the intermediate frequency “pass” range of ?lter B is widened and shifted
ampli?er 5.
‘
to a lower frequency range which includes all the
The anode I33 is supplied with positive poten
lower side band of the intermediate‘frequency
tial from any suitable source such as a battery signal. The “pass” range of ?lter C is increased
I31 connected between the anode I33 and ground. on both sides of the intermediate frequency, that
15
It will be seen that so long as current ?ows is the tuning of the ?lter is merely broadened as
through the control tube Hi, there is ?ow of indicated by the curve I6I.
,
‘
‘
current through the biasing resistor 59 of ampli
' An inspection of Figs. 2 and 3 shows that at
?er tube 5 in such a direction as to increase the the normal or highly selective setting of the re
negative bias of the control grid 56. The ceiver, the high frequency components of the side
Q. A. V. C. circuit is so adjusted that normally bands are cut off both by the circuits A and A’
this ?ow of current is sui?cient to make the con
and by the band pass ?lters B and C. It'will be
trol grid 56 so negative that the ampli?er tube 5 seen, however, that at the high ?delity setting
is made ineffective and the receiver is substan
of the receiver, that is, with the switches‘ 23, 55,
tially inoperative to receive signals.
and T! in the positions shownin Fig. 1, the‘entire
The control grid I3I of the control tube II‘! is upper side band of the radio frequency carrier is
connected to the input circuit of the recti?er tube transmitted together with the lower frequency
II 5 at a point between the secondary winding end of the lower side band. It will be noted that
I39 of the transformer I23 and a resistor I4I con
the upper side band of the radio frequency car
nected in series therewith and shunted by a ?lter rier wave corresponds to the lower side band ‘of 30
condenser I45. The cathode I29 of the control the intermediate frequency carrier wave, as in
tube II‘! is connected-to the cathode I43 of the dicated in Fig. 3. This side band inversion fol
recti?er tube I I5 whereby any potential drop ap
lows from the fact that the superhetero-dyne oscil
pearing across the resistor MI is applied to the lator frequency is higher than‘ the signal fre
grid I3I of the control tube Ill.
‘
-
quency.
So long as no signal reaches the recti?er tube
II5, the grid of the control tube II‘! is in the
same‘ potential as its cathode I29, and the cur
rent ?ow through the control tube I I1 maintains
the intermediate frequency ampli?er 5 in ‘an in
operative condition. As ‘soon as intermediate
frequency energy is impressed upon the recti?er
II5, however, the grid of the control tube II‘! is
made negative with respect to its cathode I29,
‘ due to recti?ed current ?owing in resistor I4I,
whereby the current flow through the control
tube is either decreased or stopped entirely, there
by reducing or removing the high negative po
tential from the control grid 59 of the intermedi
ate frequency ampli?er 5 and rendering the re
ceiver operative to receive signals.
_
The speci?c A. V. C. and Q. A. V. C. circuits
described in this application are disclosed and
claimed in application Serial No. 648,422, ?led
December-‘22, 1932, as the joint invention of W. L.
Carlson and L. R. Kirkwood, and assigned to the
Radio Corporation of America.
The operation of the receiver will be more
clearly understood by referring to the curves
, shown in Figs. 2 and 3.
In Fig. 2, the curves
show the selectivity of the radio frequency cir
cuits A and A’ for the conditions both of high
selectivity and high ?delity.
For the condition of high selectivity, the
switch 23 is closed and the circuits A and A’ are
tuned to the same signal frequency, the selectivity
of the two circuits combined being shown by the
dotted line curve I41. For this condition of op
eration, the switch 55 of ?lter B is-open and
switch TI of ?lter C is in its upper position to
give ?lters B and C a selectivity characteristic
shown by the dotted line curve I49 in Fig. 3.
The selectivity of the Q. A. VpC. circuit is
shown by the curve I5I in Fig. 3. It will be noted
that for the condition of high receiver selectivity,
-
For the condition of high ?delity reception, the
Q. A. V. C. circuit is tuned to a frequency within
but at one end of the “pass” range of the ?lter B
as will be apparent by comparing curves ,I5I and
I59 in Fig. 3. This new ‘relation between the
?lter circuits, it will be understood, is caused
merely by operating a'switch control‘ to shift
the tuning of the circuits A, B, and C. ‘ ‘Because
of this relation, the receiver, when set’for'high
?delity reception, must always be tuned to one 45
side band of a carrier wave before a signal ap
pears in the receiver output'circuit.
The curves in Fig. 4 show the audio frequency
gain of the receiver plotted against frequency
for the two conditions of operation. The curve
indicated at I63 is for the condition of high se 50'
lectivity, while the curve indicated at I65 is for
the condition of high ?delity reception.
.- The most important difference between thetwo
curves'is that the gain for high ?delity reception
holds up at the high frequency end after the '55
gain for normal reception has dropped to a low
value. It will be noted that the curve I55 shows
the‘ gain to be higher for low frequency signals
than for the high frequency signals. This dif
ference in gain is caused by the fact that the 60
low frequency signal components of .both side
bands are passed by the ?lter circuits.
' '
Although the receiver has been described as
adjusted for reception of the upper side band of
the radio frequency. carrier wave, it could equally 65
well be adjusted for reception of the lower side
band only. Furthermore, various otherswitch
ing arrangements for controlling the selector cir
cuits may be provided. For example, the tuning
of circuit A’ may be shifted in place of the tun
ing of circuit A; the tuning of the secondary
circuit of ?lter B instead of the primary circuit
may be changed; and the band pass character
istic of ?lter C may be shifted’ the same as for
4
2,133,808
?lter B although the circuit illustrated is advan
tageous since the gain is not changed when the
tuning is changed.
‘
It will be apparent that, instead of changing
the capacity in circuits A and B, the inductance
may be changed by proper switching.
In the case
of circuit A, however, the capacity change is
preferred since it broadens the tuning the most
at the lower carrier frequencies. At the higher
10 frequencies, as at the upper end of the broadcast
band, the tuning is normally rather broad and
need not be broadened appreciably by the switch
ing.
My invention is of particular importance where
15 the signals to be ampli?ed have such a high fre
quency that it is difficult to obtain the desired
ampli?cation. In television reception, for ex
ample, with the circuits tuned broadly enough
to receive both side bands with high ?delity, the
maximum gain per stage is about 4. By employ
ing my invention for high ?delity reception, the
gain per stage may be madeabout 6.
My invention provides improved selectivity
since on one side of the received carrier there
will be a wide spacing between the cut-off fre
quency of a ?lter and the adjacent transmis
sion channel. This improvement in selectivity
will be apparent by comparing curves I59 and
l6l in Fig. 3 since, if the tuning of the circuits
were merely broadened for high ?delity recep
tion, the selectivity curve for the receiver would
be similar to the curve l6! for ?lter C.
A furtheradvantage of my invention resides in
for converting an incoming radio frequency signal
to an intermediate frequency signal having at
least one side band, a second detector, a band
pass ?lter for passing a band .of frequencies ap
proximately the width of said side band, said
band-pass ?lter being connected between said two
detectors, a sharply resonant ?lter coupled to
said receiver at a point between said two detectors,
said sharply resonant ?lter being tuned to said
intermediate frequency, means for making said 10
receiver normally inoperative, and means for
making said receiver operative in response to the
passage of energy through said sharply resonant
?lter.
,
.
4. In a radio receiver, means for selecting a high 15
frequency modulated ‘carrier wave including a
plurality of tunable signal selecting circuits at
least one of which is adjustable to respond to
one side band of the modulated carrier wave, an
intermediate frequency ampli?er comprising a
plurality of tuned'signal selecting circuits at least
one of which is adjustable to respond to the inter
mediate frequency carrier wave and side band
corresponding to said selected high frequency
carrier wave and side band, an automatic volume 25
control signal recti?er device coupled to said
intermediate frequency ampli?er to receive the
intermediate frequency carrier wave, and means
for rendering said receiver operative to receive
signals including a signal recti?er device and 30
intermediate frequency coupling means therefor
comprising at least one tuned coupling circuit
sharply responsive to they intermediate frequency
the simplicity of the switching arrangement,
only three switches being required in the receiver
carrier wave alone.
5. In a radio receiver, means for selecting an 35
shown in Fig. 1. If the tuning were broadened
for receiving both side bands, it would be neces
sary to employ more switches.
Various other modi?cations may be made in my
incoming signal comprising a modulated carrier
having at least one side band, means for convert
ing said incoming signal to a signal comprising a
predetermined intermediate frequency carrier
40 invention without departing from the spirit and
having at least one side band, an intermediate 40
nal to an intermediate frequency signal having
signal input circuit responsive to a frequency
within the “pass” range of said tuned circuit, and 50
a quiet automatic volume control system having a
frequency ampli?er which includes a tuned cou
such limitations shall be placed thereon as are pling circuit, said tuned circuit being adjustable
necessitated by the prior art and set forth in the ' to select only said one intermediate frequency
side band, and means for making said receiver
appended claims.
operative only in response to so adjusting said
I
claim
as
my
invention:
45
converting means that said one side band falls
1. In a superheterodyne receiver, a ?rst de
tector and a tunable oscillator coupled thereto within the “pass” range of said tuned circuit, an
automatic volume control system having a tuned
for converting an incoming radio frequency sig
scope thereof, and I desire,‘therefore, that only
50 at least one side band, a second detector, a band
pass ?lter for passing signals within a band. of
frequencies approximately the width of said side
band, said band-pass ?lter being connected be
tween said two detectors, and means including a
55 sharply resonant ?lter tuned to a frequency near
one end of said band of frequencies for control
ling the operativeness of said receiver.
2. In a superheterodyne receiver, a ?rst de
tector and a tunable oscillator coupled thereto
60 for converting an incoming radio frequency sig
nal to an intermediate frequency signal having
at least one side band, a second detector, a band
pass ?lter for passing a band of frequencies ap
proximately the width‘of said side band, said
65 band-pass ?lter being connected between said two
detectors, a sharply resonant ?lter coupled to said
receiver at a point between said two detectors,
said sharply resonant ?lter being tuned to a fre
quency near one end of said band of frequencies,
70 means for making said receiver normally inopera
tive, and means for making said receiver opera
tive in response to the passage of energy through
said sharply resonant filter.
3. In a superheterodyne receiver, a ?rst de
tector and a tunable oscillator coupled thereto
tuned signal input circuit more sharply responsive
than said automatic volume control system to a
frequency also within the “pass” range of said
tuned circuit.
in 2;:
6. In a superheterodyne receiver, a ?rst de
tector tube and a tunable oscillator coupled there
to for converting a modulated incoming radio
frequency‘ signal to an intermediate frequency
signal having at least one side band, a second GO
detector tube, a plurality of ampli?er tubes, all
of said tubes being connected in cascade, a band
pass ?lter for passing a band of frequencies ap
proximately the width of said side band, said
intermediate frequency being at one end of said
band, said band-pass ?lter being connected be
tween said two detectors, and means including a '
sharply resonant ?lter tuned to said intermedi
ate frequency for increasing the gain of at least
one of said tubes in response to passage of energy 70
through said sharply resonant ?lter.
'7. In a radio receiver, means for selecting an
incoming signal comprising a modulated carrier
having at least one side band, means for selecting
said one side band of the incoming signal, means 75
2,133,808
for converting said incoming signal and side band
to a signal comprising a predetermined interme
diate frequency carrier having a corresponding
side band, a ?lter for selecting said one interme
diate frequency side band and carrier, and means
for making said receiver operative only in re
sponse to so adjusting said converting means that
said one side band falls within the “pass” range
of said ?lter.
10
‘
-8. In a superheterodyne receiver, means for
selecting an incoming radio-frequency signal in
cluding a carrier and at least one side band,
means for converting said signal to an interme
diate frequency signal including at least one side
band, a ?lter for selecting said one side band, and
means including a sharply resonant ?lter for
making said receiver operative only when erergy
at said intermediate frequency is impressed upon
said resonant ?lter, said sharply resonant ?lter
20 being tuned to a frequency lying within and at
one end of the frequency range of said ?rst ?lter.
9. In a radio receiver, means for converting an
incoming signal consisting of a modulated car
rier wave having side bands to a signal consist
ing of a carrier wave having a predetermined in
termediate frequency and having side bands,
means for selecting one of said intermediate fre
quency side bands, said selecting means includ
ing a band-pass ?lter having a “pass” range ap
proximately the Width of said one side band, a
sharply tuned ?lter tuned to a frequency within
and at one end of said “pass” range, means for
impressing at least a portion of said converted
signal upon said sharply tuned ?lter, and means
35 for making said receiver operative only when
said sharply tuned ?lter passes energy.
10. In a superheterodyne receiver, a ?rst de
tector tube and a tunable oscillator coupled there
to for converting a modulated incoming radio
frequency signal to an intermediate frequency
signal having two side bands, a second detector
tube, a ?lter connected between said detector
tubes and tuned broadly to said intermediate fre
quency whereby a portion of said side bands
45 are transmitted, means including a sharply res
onant ?lter tuned to said intermediate frequency
for increasing the response of said receiver in
response to the passage of energy through said
5
nant ?lter tuned to said intermediate frequency
for increasing the response of said receiver in
response to the passage of energy through said
sharply resonant ?lter, and means for broaden
ing the tuning of said ?rst ?lter on one side only
of said intermediate frequency when desired.
12. A radio receiver comprising means for se
lecting a signal having a carrier frequency and
at least one side band, a ?lter for selecting said
one side band only, and means including a sharp 1O
ly resonant ?lter for making said receiver oper
ative only when said one side band falls within
the “pass” range of said ?rst ?lter.
13. A radio receiver comprising means for se
lecting a signal having a carrier frequency and at 15
least one side band, a ?lter for selecting said one
side band only, and means including a sharply
resonant ?lter for making said receiver operative
only when said sharply resonant ?lter passes
energy, said sharply resonant ?lter being tuned 20
to a frequency lying within and at one end of the
frequency range of said ?rst ?lter.
14. In a radio receiver of the superheterodyne
type, a tunable radio frequency circuit for se
lecting an incoming signal, an intermediate fre 25
quency selecting ‘circuit, and means for simul
taneously shifting the tuning of said radio fre-'
quency circuit to select one side band only of
a desired signal and the tuning of said intermedi
ate frequency circuit to select the corresponding 30
intermediate frequency side band,
15. In a radio receiver, means for selecting an
incoming signal comprising a modulated carrier
having at least one side band, means for con
verting said incoming signal to a signal compris
35
ing a predetermined intermediate frequency car
rier having at least one side band, an intermedi
ate frequency ampli?er whichincludes a tuned
coupling circuit, said tuned circuit being adjust
able to select only said one intermediate fre 40
quency side band, and means for making said
receiver operative only in response to so adjust
ing said converting means that said one side
band falls within the “pass” range of said tuned
circuit.
16. In a wireless or like receiver for modulated
45,
bands and only a small portion of the other of
said side bands.
carrier-wave transmission, signal-selective means
comprising the combination of a resonant de
vice of low damping tuned to the frequency
of the carrier wave of the signal, a comparatively 50
broadly-tuned resonant device for receiving at
least one side-band of the signals at substantially
uniform amplitude, means for applying the sig
11. In a superheterodyne receiver, a ?rst de
tector tube and a tunable oscillator coupled there
nals to both of said resonant devices, means for
controlling the total output of the receiver ac 55
sharply resonant ?lter, and means for so chang
50 ing the tuning of said ?rst ?lter that it may
transmit substantially all of one of said side
to for converting incoming radio frequency sig
cording to the strength of the signals, and means '
nals to intermediate frequency signals, a second
detector tube, a ?lter connected between said de
tector tubes for passing a band of frequencies,
controlled by the output of at least one ‘of said
resonant devices for suppressing the total output
60 said intermediate frequency being in the middle
of said band, means including a sharply reso
of the receiver when minimum signals are re
ceived.
60
WENDELL L. CARLSON.
Документ
Категория
Без категории
Просмотров
0
Размер файла
943 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа