1. Decode: Added Spacewire, USB2.0, CAN XL

2. Measure:
a) Added item: UpperLower
b) Added Source: ZFx, ZMx
c) Supported zoom in the measure histogram

3. Cursors: Supported to hide Y cursors in track mode

4. Math:
a) Supported up to 8 traces
b) Added operators: Envelope, tan, atan, FFT Phase
c) FFT：peak added delta display; marker added ordering by number, amplitude and frequency
d) FFT：Added windows Blackma_Harris and Gaussian
e) Supported to hide traces

5. Analysis：
a) SignalScan added decode search
b) Eye Diagram: added Vpp measurement

6. REF: Supported to hide traces

7. Zoom:
a) ZFx supported to set horizontal scale independly; ZFx, ZMx supported to synchronize the display region with Zx
b) Supported to set Zx’ vertical scale with unified adjustment

8. Roll：
a) Supported decode in Stop mode
b) Supported Roll + Zoom in fast display mode

9. Prode: Supported CP150, HVD3106A; Supported to set external scaling of SAP2500D

10. Save/Recall:
a) Autosave supported to save pictures
b) Supported to save all channels’ data to a single file
c) FileManager：Supported to view a picture in full screen mode

11. Display:
a) Axis label supported to set the vertical label on center and right
b) Supported to change the font size

12. System: Time/date supported NTP; Supported education mode

13. Webserver: supported inverted screenshot (according to the Image style setting in the Save menu) ; Added Run/Stop virtual button

14. SCPI: Added command MANual to support to set Amplitude Strategy of Measure

15. Fixed several bugs
a) Sending SCPI commands continuously lead the instrument to frozen state

1. Decode: Added SpaceWire, CANXL; added level hysteresis

2. Math:
a) Added operators: atan, Fiter
b) FFT: added windows Blackman-Harris and Gaussian

3. Measure：
a) Added item: Bit Rate, Data Rate, UpperLower, △TimeMax、△TimeMin
b) Supported to limit the display digits of measure

4. Roll: Supported Math and decode in Stop mode

5. Webserver: supported inverted screenshot (according to the Image style setting in the Save menu); added Run/Stop button

6. Save/recall: Supported Auto Save; support “Select All” operation in FileManager

7. UI：Supported to specify Zoom region by drag a rectangle; supported movable channel label

8. Utility：Supported password for screen saver

9. SCPI： added command for △time; added command to hide right menu

10. Fixed several bugs:
a) To hide Y cursors in track mode
b) In ERES + Roll mode, head of the trace is incorrect
c) When saving a .mat file it is possible to lost the last 4 bytes
d) Issues on matching SCP current probes

1. Add DHCP function to IP addressing
2. Add Open Socket at LAN port 5025
3. Add over current protect function in a special case
4. Fix a crash fault when restoring settings
5. Modify the calibration arithmetic in 2-wire resistance
measurement 10 MOhm range
6. Add “ABORT BULK IN” ,”INITIATE CLEAR” features
to remote SCPI commands

1. Improve the UI.
2. Fix the bug in the trend chart.
3. Modify the number of file systems from 2 to 3 and copy some
configuration files to new location .This will reduce the chance of
a system crash.
4. Need to use transition software to update from old to new
version.

1. Fixed some unit faults in 06version
2. Fixed some bugs about communication with easysdm.

1. Add the customer sensor support.
2. Add the manual calibration support.
3. Optimize flash R&W design。
4. Fix some UI & SCPI bugs

1. Add and optimize the manual calibration function
2. Solve the socket communication in multiple cycles of
open/close, may not respond to the problem
3. Fix the problem that the “READ” command does not
match the description in the programming manual
4. Fix the key test screen no prompt
5. Optimize the connectivity test buzzer response speed
issues

1.Long press the left button: one beep sounds,
and the prompt “CC mode prompt tone
disabled” plays.
Long press the left button again: two beeps
sound, and the prompt “CC mode prompt tone
enabled” plays.

1.This firmware is only compatible with
hardware version V6.1.
2.The MCU has been changed to GD32F427.
Firmware versions 1.01.01.02.XXX cannot be
upgraded.

1.Long press the left button: one beep sounds,
and the prompt “CC mode prompt tone
disabled” plays.
Long press the left button again: two beeps
sound, and the prompt “CC mode prompt tone
enabled” plays.

1. Fix: The UI was not updated in time when the power meter was pulled out.
2. Fix: GPIB Address can not be changed.
3. Fix: The mouse is hidden under VNC.
4. Fix: Some wrong SCPI commands were executed.
5. Optimize function with OCXO module.
6. Optimize power meter function.

1. Fix: In the custom mode, when save the state, some items are not saved.
2. Fix: Arb mode and pulse mode conflict. Now they can work simultaneously.
3. Fix: In Arb mode, there are some spurs, when On/Off the RF Mode button.
4. Fix: Some problems about LAN setting, VNC

1. Reduce the overshoot in the pulse function
2. Add pause function and the amplitude can be changed during pause status in
frequency step sweep mode.
3. Added some setting’s SCPI commands.

1. Added user manual calibration and verification function
(option).
2. Added the function that the number of vertical grid can be
set.
3. Added the function of supporting logarithmic display of
vertical coordinates.
4. Added point limit function

1. Added Pulse modulation function.

1. Fixed the range limits for frequency and power in mixer
measurements.
2. Fixed the trace title bar color to match the memory trace
color.

1.Add manual configuration of DC under TDR.
2.Add calibration overwrite function.
3.Optimize synchronization of external triggers for pulse
measurements.

1. Add material measurement function option.
2. Add switch matrix expansion multi-port application options.

1. Add gain compression measurement and vector mixing
measurement function.

Features and Enhancements:
1. Added Automatic Fixture Removal.
2. Added Noise Figure Measurement.
3. Added Power Meter Viewer Dialog.
4. Added support for cal kits with Sliding Load and Offset
Load.
5. Added support for HiSLIP communication protocol.
Bug Fixes:
1. Fixed a problem when changing IF bandwidth.
2. Fixed issue where changing directory in the File Browser
would cause GUI crash.
3. Fixed issue where multi-channel calibration would cause
crash.
4. Fixed issue where cal file would not correctly save or recall.
5. Fixed issue where sweep time would not estimate correctly
after adding a SA channel
6. Fixed issue with calibration type list display.
7. Fixed a bug where loading S2P file for 2-port de-embedding
would cause crash
8.Fixed issue with calibrating with a DATA-BASED
calibration kit.
9. Fixed issue with recalling CSV or SNP data files.

1. Add shortcut buttons at the toolbar.
2. Fix the stuttering problem when adjusting the brightness of
the grid in the waveform area.
3. Solve the problem of probabilistic crashes when opening
dialogs.
4. File storage shortcut keys support more types.
5. Support more power meters.
6. Add picture editing function to the screenshot dialog.
7. Adds peak reference function for bandwidth search.
8. Modify the contents of the Chinese and English help files
9. Modify the user receiver calibration process.
10. The input box will pop up automatically when using the
toolbar button to add Marker.

1.Solved the menu button is not updated when the electronic
calibration module is inserted or removed.
2. Fixed a bug that the touch screen may crash under some
cases.
3. Fixed an option installation bug.

1. Added spectrum analyzer option.
2. Fixed input bug in network configuration window.
3. Fixed mouse click input box crash bug.
4. Increased the touch-sensitive area of the DHCP checkbox.
5. Modified the policy when the DHCP request fails.

1. Added independent configuration function of emission
source in spectrum mode.
2. Optimized the sweep process.
3. Optimized TDR interface.
4. Added command for transferring file data.
5. Added marker->SA commands.

1. Added Frequency Offset function.
2. Optimized some functions of spectrum analysis.
3. Added status bar to display smooth status.
4. Added advanced mode for bandwidth search, support
frequency percentage bandwidth setting function.
5. Optimized the Marker->Delay algorithm.

Features and Enhancements:
1. Added Automatic Fixture Removal.
2. Added Noise Figure Measurement.
3. Added Power Meter Viewer Dialog.
4. Added support for cal kits with Sliding Load and Offset
Load.
5. Added support for HiSLIP communication protocol.
Bug Fixes:
1. Fixed a problem when changing IF bandwidth.
2. Fixed issue where changing directory in the File Browser
would cause GUI crash.
3. Fixed issue where multi-channel calibration would cause
crash.
4. Fixed issue where cal file would not correctly save or recall.
5. Fixed issue where sweep time would not estimate correctly
after adding a SA channel
6. Fixed issue with calibration type list display.
7. Fixed a bug where loading S2P file for 2-port de-embedding
would cause crash
8.Fixed issue with calibrating with a DATA-BASED
calibration kit.
9. Fixed issue with recalling CSV or SNP data files.

1. Fixed “button does not respond after self test”

1. Add “PNG“ file type for screenshot.
2. Support TG in RBW less than 30 kHz.
3. Modify default TG output power, -20 dBm in spectrum ananlyzer mode and 0 dBm in
reflection measure mode, and some other TG issues.
4. Updating the format of “LIM“ file. After this firmware , the old limit files will not be
supported. You can recreate them through “EasySpectrum” free software easily.
5. After this firmware, do not support downgrade operation.

1. This firmware must be upgraded from V1.2.8.1 or later. If your SSA3000X has an
earlier version, please update to V1.2.8.1 first and then proceed to update to the
latest version.
2. Add socket/telnet-scpi, you can operate remote control through LAN port without
NI-VISA installed. Please see SSA3000X‘s Programming Guide for more details.
3. Change two limit lines in different colours.
4. When quit from TG, stay in“Auto” sweep.
5. Lower some spurs when FFT.
6. Improve the stability.

1. This firmware must be upgraded from V1.2.8.1 or later. If your SSA3000X has an
earlier version, please update to V1.2.8.1 first and then proceed to update to the
latest version.
2. Improved the stability of sweep and avg detect.
3. Fixed some bugs on sweep, frequncy counter and Log-Log scale.
4. Fixed some bugs on SCPI and the AMK option.

1. This firmware must be upgraded from V1.2.8.1 or later. If your SSA3000X has an
earlier version, please update to V1.2.8.1 first and then proceed to update to the
latest version.
2. Fixed v1.2.8.5 bugs on Refl Mode.
3. Fixed v1.2.8.5 bugs on language and file

1. This firmware must be upgraded from V1.2.8.1 or later. If your SSA3000X
has an earlier version, please update to V1.2.8.1 first and then proceed to
update to the latest version.
2. Fixed bugs on peak search and next peak.
3. Optimize SCPI commands for peak table, screenshot, etc.
4. Optimize the LOG X-scale for EMI test.
5. Optimize the Quasi-Peak detector accuracy for EMI test

Notice:
This firmware must be upgraded from v2.1.1.1 or later. If your analyzer has an earlier version, don’t use this FW to update.

Improvements:
Optimize the Ref level and Att couple

Solved Issues:
Fix the zero sweep type when fft in SA mode
Fix the OPC response in EMI mode

Improvements:
• Optimize trace, marker, signal track, TG normalization，Reflection measurement in SA Mode
• Optimize web server UI
Solved Issues:
• Fixed video trigger fail, errors in Harmonic measurement in SA Mode
• Fixed spectrum amplitude error, meas error, waveform discontinue in MA Mode
• Fixed English help, system message

Improvements:
• Add Limit mask offset in SA mode
• TG Level adjustable in Reflection Meas
Solved Issues:
• Fixed AM and FM symbol rate error, Lpf coefficient error, in AMA mode
• Fixed Filter bandwidth error in DMA mode
• Fixed Freq counter error in SA mode
• Fixed Harmonic error in SA mode
• Help Display error

New Functionality:
• Update EMI option to a new EMI measurement mode
Improvements:
• Improve TG output harmonic performance
• Update Help file
Solved Issues:
• Fix ADC overload warning
• Fix Ch Power calculation bug in small span

Solved Issues:
• Fix avg power bug in EMI Mode
• Fix amplitude bug in AMA Mode
• Fix peak search bug in SCPI command

Solved Issues:
• Fix avg power bug in EMI Mode
• Fix amplitude bug in AMA Mode
• Fix peak search bug in SCPI command

New Functionality:
• Add EMI filter in SA for EMI option
Solved Issues:
• Optimize the TG flatness and control procedure
• Optimize Help
• Fix Correction, .csv file, add peak numbers to 20 in EMI mode
• Fix amplitude error in DMA Mode
• Fix upgrade failure issue

New Functionality:
• Add EMI filter in SA for EMI option
Solved Issues:
• Optimize the TG flatness and control procedure
• Optimize Help
• Fix Correction, .csv file, add peak numbers to 20 in EMI mode
• Fix amplitude error in DMA Mode
• Fix upgrade failure issue

New Functionality:
• Add EMI filter in SA for EMI option
Solved Issues:
• Optimize the TG flatness and control procedure
• Optimize Help
• Fix Correction, .csv file, add peak numbers to 20 in EMI mode
• Fix amplitude error in DMA Mode
• Fix upgrade failure issue

This version con not be rolled back
• Fix TG switch error at small RBW
• Fix Help and Limit file lost when Factory reset
• Fix CNR calc error when no peak found
• Fix OBW result overflow
• Fix Harmonic calc error at 100Hz RBW
• Fix Reflection Open+Short calibration action
• Fix spectrum amplitude error in DMA mode
• Optimize EMI .csv file content to all signal list
• Optimize EMI peak search
• Optimize Auto cal process
• Add Peak search to Spectrum in DMA mode

This version con not be rolled back
• Fix TG switch error at small RBW
• Fix Help and Limit file lost when Factory reset
• Fix CNR calc error when no peak found
• Fix OBW result overflow
• Fix Harmonic calc error at 100Hz RBW
• Fix Reflection Open+Short calibration action
• Fix spectrum amplitude error in DMA mode
• Optimize EMI .csv file content to all signal list
• Optimize EMI peak search
• Optimize Auto cal process
• Add Peak search to Spectrum in DMA mode

• This version can not be rolled back
• Fix TG switch error at small RBW
• Fix Help and Limit file lost when Factory reset
• Fix CNR calc error when no peak found
• Fix OBW result overflow
• Fix Harmonic calc error at 100Hz RBW
• Fix Reflection Open+Short calibration action
• Fix spectrum amplitude error in DMA mode
• Optimize EMI .csv file content to all signal list
• Optimize EMI peak search
• Optimize Auto cal process
• Add Peak search to Spectrum in DMA mode

• Fix TG switch error at small RBW
• Fix Help and Limit file lost when Factory reset
• Fix Auto open delay unit error in VNA mode
• Fix CNR calc error when no peak found
• Fix OBW result overflow
• Fix Harmonic calc error at 100Hz RBW
• Fix Reflection Open+Short calibration action
• Fix spectrum amplitude error in DMA mode
• Optimize EMI .csv file content to all signal list
• Optimize EMI peak search
• Optimize Auto cal process
• Add Peak search to Spectrum in DMA

Fixed several bugs
a) A bug in file system could cause the
generator never startup
b) Can not wake up from screen saver from
time to time

Fixed several bugs
a) A bug in P12R1 which could cause the
update to fail
b) Some typo in English help system

It is strongly recommended to update to the latest
release because in some previous release exists
some serious bug which could cause the generator
never startup
1. Supported system recovery from the U-disk
2. Supported Rev.C hardware with Over Voltage
Protection

Fixed the incorrect sweep direction bug

Fixed the abnormal display issue during start-up on
some units with previous releases. It is not
necessary to update to this version if the unit has
no such a problem.

1. Supported to automatically enable the output
after power-on: Utility | Output Setup | Power
on State
2. Compatible with Rev.E hardware

1. Added statistic function in counter mode
2. Supported using method 2 from our “generating
mulitphase waveforms” application note (refer to
http://www.siglentamerica.com/prodcut-pxzl.aspx?id=9
0&tid=16&T=2) to synchronize 2 units of SDG2000X
3. Fixed some bugs
a) A bug in file system could cause the generator
never startup
b) DHCP does not run at power up
c) Channel lock phase can be wrong in modulation
sometimes
d) Error in calculation of frequency deviation in
counter mode
e) Instrument does not allow CH1 and CH2 to both
use the external input for the modulation source
simultaneously in tracking mode
f) Downward compatibility of .xml state file
g) Unable to delete files with uncommon character(s)
in their names

1. Allow 0 Hz for CH Frequency In MOD Modes PM, AM,
DSB-AM, ASK, PSK
2. Allow MOD frequency > CH Frequency In MOD Modes
PM, DSB AM, ASK
3. Allow DSB-AM, AM MOD Modes In TrueArb Mode
4. Up Followed by Down Sweep Mode is Supported in
Linear Sweep (No Change for Log Sweep)
5. Added ARB waveform name to display, allowing user to
know what Arb waveform is loaded
6. Fixed some bugs
a) Arb Waveforms In DDS Mode Have One (Small)
Glitch Per Cycle
b) Built in Ramp waveform has a flat spot issue at the
rising slope zero crossing right at the SYNC pulse.
c) Power Up Last Does Not Remember
SRate/Frequency Setting
d) MOD Type = DSB AM Has Amplitude Issues

1. Supported system recovery from U-disk.
2. Fixed a bug which may cause the generator report a
false over voltage alarm when start-up.

Optimized calibration and PV process on the production line.

1. Changed the amplitude strategy of AM modulation: The
carrier stays fixed at the amplitude, regardless of the
modulation setting.
2. Increased the upper limit of Harmonics number from 10
to 16.
3. Supported Multi-Device Synchronization.
4. Supported Up followed by Down Sweep mode in Linear
sweep (no change for Log sweep).
5. Added an icon to indicate clock source is internal or
external.
Internal: External:
External and the clock is lost:
6. Changed the clock switch strategy: When the clock
source is set to External and no actual external clock
signal is being received, the clock source will not switch
to Internal automatically but the clock icon will
indicate that external clock is lost
7. Supported specifying Arb type by remote control when
the modulating waveform is Arb.
8. Optimized the UI of selecting built-in arbs
9. Supported changing the unit of amplitude without any
amplitude change by long pressing the “Amplitude”
softkey.
10. Added “User” option under “PowerOn Setting”.
11. Added “Normal” as a new UI color style.
12. Added memory space information in Store/Recall UI.
13. Optimized response of the universal knob
14. Added indicator for double function of the soft keys
=>
15. Removed the warning message when parameter is set
to a value beyond the limit
16. Fixed several bugs
a) [2017/04/07-92573] Digit changes when setting
delay of Pulse by the knob
b) Amplitude unit “dBm” is not remembered after a
reboot

Optimized debounce of the front panel buttons.

1. Compatible with Rev.F hardware
2. Support trig dual channel separated when use mannul
trigger.
3. Support using another channel as the modulation
source
4. Support setting the output frequency after the
completion of sweep
5. Counter add fast measurement mode
6. Change the square waveform data used in square FM
modulation

The first formal release

1. Optimized TrueArb algorithm and added 3 types of
interpolation: sinc, sinc27 and sinc13
2. Optimized jitter performance of Square and Pulse
3. Optimized algorithm of Noise generating so the bandwidth
setting lower limit of Noise optimized from 80 MHz to 1
mHz
4. [2017/12/22-174663] Changed the clock switch strategy:
When the clock source is set to External and no actual
external clock signal is being received, the clock source
will not switch to Internal automatically but the clock icon
will indicate that external clock is lost
5. [2017/12/22-174663] Changed default state of 10 MHz
Out to “Disable”
6. Added Slave Delay option in Multi-Device Synchronization
function
7. Added indicator for double function of the soft keys
=>
8. Fixed the following bugs:
a) Crashes when downloading 20 Mpts waveform data
from the EasyWave program
b) Inaccurate burst delay
c) In TrueArb mode enabling AM with large amplitude
may trigger OVP
d) Switching the waveform from IQ to sine with large
amplitude may trigger OVP
e) Switching off the output on the SDG6kX only drops
the output level by approx 20 dB but does not
completely switch it off

1. Removed the warning message when parameter is set to
a value beyond the limit
2. Supported to copy/paste/delete folder in Store/Recall file
manager
3. Optimized initialization time when the waveform is
switched between IQ and other waveforms
4. Supported phase compensation in IQ mode
5. Fixed several bugs:
a) [2018/09/14-924144, 2018/09/14-937446] Signals
get interrupted upon timing-related change of the
settings in Independent mode
b) Anomaly on square/pulse waveform with some
setting
c) [2018/11/06-92208] Anomaly on arb waveform when
toggle the “ArbMode” from DDS to TrueArb and
back to DDS in Independent mode

1. Changed the upper limit of carrier frequency (sine) in
Burst mode from 300 MHz to 500 MHz
2. Added some missing SCPI commands
3. Fixed several bugs:
a) Messed up signal after switching from 500 MHz sine
to square in independent mode
b) Glitches when outputting pulses under certain
circumstances in independent mode

1. Allowed one channel to modulate the other
2. Supported Burst in TrueArb mode
3. Supported Burst Counter in Burst mode so the number of
burst trains can be set to > 1 when trigger source =
external or manual
4. Added an option to let the SDG start with activated
outputs
5. Added 50 ohm output impedance text in the UI
6. Able to remember the digit of a parameter that had been
modified
7. Fixed several bugs:
a) DDS interpolation bug
b) Switching on/off output causes random phase
deviation between channels in Track mode
c) Incorrect square/pulse waveform initialization in
some cases
d) Unable to store the level settings for noise
e) Unable to recognize the command MODE
PHASE-LOCKED
f) Freezing issue when being written a 20MB long file
with the EasyWaveX
g) The setting “BANDSET” with Waveform = NOISE
leads to inconsistent behavior on the Noise
Bandwidth of the output signal; The real-time noise
bandwidth on channel 2 is changed if an AM sine
modulation is switched on channel 1
h) Unable to install the IQ option before 30 trials run out

1. Support SDS1000X HD and SDS800X HD, 8.2.x is only applicable to SDS1000X HD and SDS800X HD.

Fixed some issue on the production line. From user’s perspective no difference with 1.2.3.1

1. Measure: added new items UpLower, △TimeMax, △TimeMin
2. Math：FFT – added windows Blackman-Harris and Gaussian
3. Decode: Added SpaceWire, CANXL
4. Roll: Supported Math in Stop mode
5. Channel: in Eres mode to display the corresponding bandwidth
information in the descriptor box
6. Digital
a) Digital channels ASCII decoding requested
b) Optimized labels’ display
7. Save/Recall：
a) Supported AutoSave
b) File Manager: Supported to Select All
8. WebServer: supported inverted screenshot (according to the Image
style setting in the Save menu); added virtual front panel; added
Run/Stop button
9. UI：
a) Supported custom colors for XY trace
b) Supported to disable Time/Date display
c) Supported to specify Zoom region by drag a rectangle
10. Utility:
a) Supported password for screen saver
b) Key test: Supported to test the rotation direction of the encoders
11. Remote control:
a) a) added commands for counter
b) added commands for △time measurement
12. Fixed several bugs:
a) When saving inverted screenshot as JPG, PNG, trace color of
channels changes
b) SCPI commands don’t work in some cases setting horizontal
parameters
c) Phase measure doesn’t work in some case
d) In Eres mode, abnormal display on trace with 10Mpts length
13. Some SCPI issue on digital channels

Optimized Self-cal time from 52 minutes to 22 minutes

1. Fixed several bugs:
a) Add edge trigger for any edge trigger type
b) Bandwidth Limitation in Roll Mode

1. Fixed several bugs:
a) Add edge trigger for any edge trigger type
b) Bandwidth Limitation in Roll Mode

Resolved the issue where channels could not be triggered independently when both channels were in manual trigger mode.

1. Decode: Added SPMI, Spacewire, USB2.0, CANXL

2. Math:

a) Added operators: tan, atan, envelope, delay, FFT phase

b) FFT: added windows Blackman-Harris and Gaussian

c) Formular editor: supported measure item as the component of a formula

d) Supported Trend and Track as math trace

3. Measure：

a) Added item: Bit Rate, UpperLower

b) Supported to limit the display digits of measure

c) Supported to display up to 24 items at the same time

4. Analysis:

a) Added Double Pulse Test

b) Added Serial Test

5. Probe: Supported SDP6150A, SDP6150D

6. Roll: Supported Math and track cursors in Stop mode

7. Display: Supported custom colors for XY trace

8. Webserver: supported inverted screenshot (according to the Image
style setting in the Save menu); added virtual front panel

9. Save/recall: Supported full screen mode when preview an image;
supported to save multi channels data as a single file; supported Auto
Save;

10. Utility：Added English help; Supported password for screen saver

11. Fixed several bugs:

a) The instrument becomes slower after long time run

b) Webserver: some control issue in full-screen mode

c) Cannot save a Memory trace to file
d) OPC command response error

1. Support SMB and NTP functions
2. Optimize the reading time for continuously switching gears at slow speeds
3. Repair the malfunction
a) BUG for incorrect readings when set to fast
b) The problem of manually setting the number of grids under the histogram failing
c) The issue of not saving time settings after restarting
d) The issue of failed first screenshot